diff --git a/src/lib.rs b/src/lib.rs
index 9354f010..aefd89ca 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -108,18 +108,17 @@ extern crate serialize;
 #[cfg(test)]
 extern crate test;
 
-use std::num::{Zero, One};
 use std::cmp;
 pub use traits::{PartialLess, PartialEqual, PartialGreater, NotComparable};
 pub use traits::{
     Absolute,
     AbsoluteRotate,
-    NumPnt,
-    NumVec,
     ApproxEq,
     Axpy,
     Basis,
     BaseFloat,
+    BaseNum,
+    Bounded,
     Cast,
     Col,
     ColSlice, RowSlice,
@@ -143,6 +142,9 @@ pub use traits::{
     Mat,
     Mean,
     Norm,
+    NumPnt,
+    NumVec,
+    One,
     Orig,
     Outer,
     POrd,
@@ -160,7 +162,8 @@ pub use traits::{
     Translate, Translation,
     Transpose,
     UniformSphereSample,
-    VecAsPnt
+    VecAsPnt,
+    Zero
 };
 
 pub use structs::{
@@ -336,6 +339,12 @@ pub fn zero<T: Zero>() -> T {
     Zero::zero()
 }
 
+/// Tests is a value is iqual to zero.
+#[inline(always)]
+pub fn is_zero<T: Zero>(val: &T) -> bool {
+    val.is_zero()
+}
+
 /// Create a one-valued value.
 ///
 /// This is the same as `std::num::one()`.
diff --git a/src/linalg/decompositions.rs b/src/linalg/decompositions.rs
index 63f68043..f9f6beff 100644
--- a/src/linalg/decompositions.rs
+++ b/src/linalg/decompositions.rs
@@ -1,4 +1,3 @@
-use std::num::Zero;
 use traits::operations::{Transpose, ApproxEq};
 use traits::structure::{ColSlice, Eye, Indexable, Diag, SquareMat, BaseFloat};
 use traits::geometry::Norm;
@@ -52,7 +51,7 @@ pub fn qr<N, V, M>(m: &M) -> (M, M)
     for ite in range(0u, iterations) {
         let mut v = r.col_slice(ite, ite, rows);
         let alpha =
-            if unsafe { v.unsafe_at(ite) } >= Zero::zero() {
+            if unsafe { v.unsafe_at(ite) } >= ::zero() {
                 -Norm::norm(&v)
             }
             else {
@@ -62,7 +61,7 @@ pub fn qr<N, V, M>(m: &M) -> (M, M)
             let x = v.unsafe_at(0);
             v.unsafe_set(0, x - alpha);
         }
-        if !v.normalize().is_zero() {
+        if !::is_zero(&v.normalize()) {
             let qk: M = householder_matrix(rows, ite, v);
             r = qk * r;
             q = q * Transpose::transpose_cpy(&qk);
diff --git a/src/structs/chol.rs b/src/structs/chol.rs
deleted file mode 100644
index 64f938ab..00000000
--- a/src/structs/chol.rs
+++ /dev/null
@@ -1,27 +0,0 @@
-// use lower_triangular::LowerTriangularMat;
-// 
-// /// Choleski factorization.
-// pub trait Chol<N> {
-//     /// Choleski LL* factorization for a symetric definite positive matrix.
-//     fn chol(self) -> LowerTriangularMat<N>;
-// }
-// 
-// impl<N> Chol<N> for DMat<N> {
-//     fn chol(self) -> LowerTriangularMat<N> {
-//     }
-// }
-// 
-// impl<N> Chol<N> for LowerTriangularMat<N> {
-//     fn chol(self) -> LowerTriangularMat<N> {
-//     }
-// }
-// 
-// impl<N> Chol<N> for UpperTriangularMat<N> {
-//     fn chol(self) -> LowerTriangularMat<N> {
-//     }
-// }
-// 
-// impl<N> Chol<N> for DiagonalMat<N> {
-//     fn chol(self) -> LowerTriangularMat<N> {
-//     }
-// }
diff --git a/src/structs/crout.rs b/src/structs/crout.rs
deleted file mode 100644
index db43a5b8..00000000
--- a/src/structs/crout.rs
+++ /dev/null
@@ -1,6 +0,0 @@
-use lower_triangular::LowerTriangularMat;
-
-pub trait Crout<N> {
-    /// Crout LDL* factorization for a symmetric definite indefinite matrix.
-    fn crout(self, &mut DiagonalMat<N>) -> LowerTriangularMat<N>;
-}
diff --git a/src/structs/dmat.rs b/src/structs/dmat.rs
index 174676d3..15815318 100644
--- a/src/structs/dmat.rs
+++ b/src/structs/dmat.rs
@@ -5,12 +5,11 @@
 use std::cmp;
 use std::rand::Rand;
 use std::rand;
-use std::num::{One, Zero, Num};
 use traits::operations::ApproxEq;
 use std::mem;
 use structs::dvec::{DVec, DVecMulRhs};
 use traits::operations::{Inv, Transpose, Mean, Cov};
-use traits::structure::{Cast, ColSlice, RowSlice, Diag, Eye, Indexable, Shape};
+use traits::structure::{Cast, ColSlice, RowSlice, Diag, Eye, Indexable, Shape, Zero, One, BaseNum};
 use std::fmt::{Show, Formatter, Result};
 
 
@@ -55,7 +54,7 @@ impl<N: Zero + Clone> DMat<N> {
     ///   components.
     #[inline]
     pub fn new_zeros(nrows: uint, ncols: uint) -> DMat<N> {
-        DMat::from_elem(nrows, ncols, Zero::zero())
+        DMat::from_elem(nrows, ncols, ::zero())
     }
 
     /// Tests if all components of the matrix are zeroes.
@@ -67,7 +66,7 @@ impl<N: Zero + Clone> DMat<N> {
     #[inline]
     pub fn reset(&mut self) {
         for mij in self.mij.iter_mut() {
-            *mij = Zero::zero();
+            *mij = ::zero();
         }
     }
 }
@@ -84,7 +83,7 @@ impl<N: One + Clone> DMat<N> {
     /// Builds a matrix filled with a given constant.
     #[inline]
     pub fn new_ones(nrows: uint, ncols: uint) -> DMat<N> {
-        DMat::from_elem(nrows, ncols, One::one())
+        DMat::from_elem(nrows, ncols, ::one())
     }
 }
 
@@ -191,7 +190,7 @@ impl<N: One + Zero + Clone> Eye for DMat<N> {
         let mut res = DMat::new_zeros(dim, dim);
 
         for i in range(0u, dim) {
-            let _1: N  = One::one();
+            let _1: N  = ::one();
             res[(i, i)]  = _1;
         }
 
@@ -302,7 +301,7 @@ impl<N: Clone + Mul<N, N> + Add<N, N> + Zero> DMatMulRhs<N, DMat<N>> for DMat<N>
 
         for i in range(0u, left.nrows) {
             for j in range(0u, right.ncols) {
-                let mut acc: N = Zero::zero();
+                let mut acc: N = ::zero();
 
                 unsafe {
                     for k in range(0u, left.ncols) {
@@ -327,7 +326,7 @@ DMatMulRhs<N, DVec<N>> for DVec<N> {
         let mut res : DVec<N> = unsafe { DVec::new_uninitialized(left.nrows) };
 
         for i in range(0u, left.nrows) {
-            let mut acc: N = Zero::zero();
+            let mut acc: N = ::zero();
 
             for j in range(0u, left.ncols) {
                 unsafe {
@@ -351,7 +350,7 @@ DVecMulRhs<N, DVec<N>> for DMat<N> {
         let mut res : DVec<N> = unsafe { DVec::new_uninitialized(right.ncols) };
 
         for i in range(0u, right.ncols) {
-            let mut acc: N = Zero::zero();
+            let mut acc: N = ::zero();
 
             for j in range(0u, right.nrows) {
                 unsafe {
@@ -366,8 +365,7 @@ DVecMulRhs<N, DVec<N>> for DMat<N> {
     }
 }
 
-impl<N: Clone + Num>
-Inv for DMat<N> {
+impl<N: Clone + BaseNum + Zero + One> Inv for DMat<N> {
     #[inline]
     fn inv_cpy(m: &DMat<N>) -> Option<DMat<N>> {
         let mut res : DMat<N> = m.clone();
@@ -395,7 +393,7 @@ Inv for DMat<N> {
             let mut n0 = k; // index of a non-zero entry
 
             while n0 != dim {
-                if unsafe { self.unsafe_at((n0, k)) } != Zero::zero() {
+                if unsafe { self.unsafe_at((n0, k)) } != ::zero() {
                     break;
                 }
 
@@ -500,7 +498,7 @@ impl<N: Clone> Transpose for DMat<N> {
     }
 }
 
-impl<N: Num + Cast<f64> + Clone> Mean<DVec<N>> for DMat<N> {
+impl<N: BaseNum + Cast<f64> + Zero + Clone> Mean<DVec<N>> for DMat<N> {
     fn mean(m: &DMat<N>) -> DVec<N> {
         let mut res: DVec<N> = DVec::new_zeros(m.ncols);
         let normalizer: N    = Cast::from(1.0f64 / Cast::from(m.nrows));
@@ -518,7 +516,7 @@ impl<N: Num + Cast<f64> + Clone> Mean<DVec<N>> for DMat<N> {
     }
 }
 
-impl<N: Clone + Num + Cast<f64> + DMatDivRhs<N, DMat<N>>> Cov<DMat<N>> for DMat<N> {
+impl<N: Clone + BaseNum + Cast<f64> + DMatDivRhs<N, DMat<N>>> Cov<DMat<N>> for DMat<N> {
     // FIXME: this could be heavily optimized, removing all temporaries by merging loops.
     fn cov(m: &DMat<N>) -> DMat<N> {
         assert!(m.nrows > 1);
diff --git a/src/structs/dvec.rs b/src/structs/dvec.rs
index f7a643a2..e32594d7 100644
--- a/src/structs/dvec.rs
+++ b/src/structs/dvec.rs
@@ -2,14 +2,13 @@
 
 #![allow(missing_docs)] // we hide doc to not have to document the $trhs double dispatch trait.
 
-use std::num::{Zero, One, Num};
 use std::rand::Rand;
 use std::rand;
 use std::slice::{Items, MutItems};
 use traits::operations::ApproxEq;
 use std::iter::FromIterator;
 use traits::geometry::{Dot, Norm};
-use traits::structure::{Iterable, IterableMut, Indexable, Shape, BaseFloat};
+use traits::structure::{Iterable, IterableMut, Indexable, Shape, BaseFloat, BaseNum, Zero, One};
 
 /// Heap allocated, dynamically sized vector.
 #[deriving(Eq, PartialEq, Show, Clone)]
@@ -87,7 +86,7 @@ pub struct DVec1<N> {
 }
 
 small_dvec_impl!(DVec1, 1, DVec1MulRhs, DVec1DivRhs, DVec1AddRhs, DVec1SubRhs, 0)
-small_dvec_from_impl!(DVec1, 1, Zero::zero())
+small_dvec_from_impl!(DVec1, 1, ::zero())
 
 
 /// Stack-allocated, dynamically sized vector with a maximum size of 2.
@@ -97,7 +96,7 @@ pub struct DVec2<N> {
 }
 
 small_dvec_impl!(DVec2, 2, DVec2MulRhs, DVec2DivRhs, DVec2AddRhs, DVec2SubRhs, 0, 1)
-small_dvec_from_impl!(DVec2, 2, Zero::zero(), Zero::zero())
+small_dvec_from_impl!(DVec2, 2, ::zero(), ::zero())
 
 
 /// Stack-allocated, dynamically sized vector with a maximum size of 3.
@@ -107,7 +106,7 @@ pub struct DVec3<N> {
 }
 
 small_dvec_impl!(DVec3, 3, DVec3MulRhs, DVec3DivRhs, DVec3AddRhs, DVec3SubRhs, 0, 1, 2)
-small_dvec_from_impl!(DVec3, 3, Zero::zero(), Zero::zero(), Zero::zero())
+small_dvec_from_impl!(DVec3, 3, ::zero(), ::zero(), ::zero())
 
 
 /// Stack-allocated, dynamically sized vector with a maximum size of 4.
@@ -117,7 +116,7 @@ pub struct DVec4<N> {
 }
 
 small_dvec_impl!(DVec4, 4, DVec4MulRhs, DVec4DivRhs, DVec4AddRhs, DVec4SubRhs, 0, 1, 2, 3)
-small_dvec_from_impl!(DVec4, 4, Zero::zero(), Zero::zero(), Zero::zero(), Zero::zero())
+small_dvec_from_impl!(DVec4, 4, ::zero(), ::zero(), ::zero(), ::zero())
 
 
 /// Stack-allocated, dynamically sized vector with a maximum size of 5.
@@ -127,7 +126,7 @@ pub struct DVec5<N> {
 }
 
 small_dvec_impl!(DVec5, 5, DVec5MulRhs, DVec5DivRhs, DVec5AddRhs, DVec5SubRhs, 0, 1, 2, 3, 4)
-small_dvec_from_impl!(DVec5, 5, Zero::zero(), Zero::zero(), Zero::zero(), Zero::zero(), Zero::zero())
+small_dvec_from_impl!(DVec5, 5, ::zero(), ::zero(), ::zero(), ::zero(), ::zero())
 
 
 /// Stack-allocated, dynamically sized vector with a maximum size of 6.
@@ -137,4 +136,4 @@ pub struct DVec6<N> {
 }
 
 small_dvec_impl!(DVec6, 6, DVec6MulRhs, DVec6DivRhs, DVec6AddRhs, DVec6SubRhs, 0, 1, 2, 3, 4, 5)
-small_dvec_from_impl!(DVec6, 6, Zero::zero(), Zero::zero(), Zero::zero(), Zero::zero(), Zero::zero(), Zero::zero())
+small_dvec_from_impl!(DVec6, 6, ::zero(), ::zero(), ::zero(), ::zero(), ::zero(), ::zero())
diff --git a/src/structs/dvec_macros.rs b/src/structs/dvec_macros.rs
index f033d374..5a6d9b3c 100644
--- a/src/structs/dvec_macros.rs
+++ b/src/structs/dvec_macros.rs
@@ -19,7 +19,7 @@ macro_rules! dvec_impl(
             /// * `dim` - The dimension of the vector.
             #[inline]
             pub fn new_zeros(dim: uint) -> $dvec<N> {
-                $dvec::from_elem(dim, Zero::zero())
+                $dvec::from_elem(dim, ::zero())
             }
 
             /// Tests if all components of the vector are zeroes.
@@ -106,7 +106,7 @@ macro_rules! dvec_impl(
             /// * `dim` - The dimension of the vector.
             #[inline]
             pub fn new_ones(dim: uint) -> $dvec<N> {
-                $dvec::from_elem(dim, One::one())
+                $dvec::from_elem(dim, ::one())
             }
         }
 
@@ -142,7 +142,7 @@ macro_rules! dvec_impl(
                 for i in range(0u, dim) {
                     let mut basis_element : $dvec<N> = $dvec::new_zeros(dim);
 
-                    basis_element.set(i, One::one());
+                    basis_element.set(i, ::one());
 
                     res.push(basis_element);
                 }
@@ -161,7 +161,7 @@ macro_rules! dvec_impl(
                 for i in range(0u, dim) {
                     let mut basis_element : $dvec<N> = $dvec::new_zeros(self.len());
 
-                    basis_element.set(i, One::one());
+                    basis_element.set(i, ::one());
 
                     if res.len() == dim - 1 {
                         break;
@@ -175,7 +175,7 @@ macro_rules! dvec_impl(
                         elt = elt - *v * Dot::dot(&elt, v)
                     };
 
-                    if !ApproxEq::approx_eq(&Norm::sqnorm(&elt), &Zero::zero()) {
+                    if !ApproxEq::approx_eq(&Norm::sqnorm(&elt), &::zero()) {
                         res.push(Norm::normalize_cpy(&elt));
                     }
                 }
@@ -225,12 +225,12 @@ macro_rules! dvec_impl(
             }
         }
 
-        impl<N: Num + Clone> Dot<N> for $dvec<N> {
+        impl<N: BaseNum + Clone> Dot<N> for $dvec<N> {
             #[inline]
             fn dot(a: &$dvec<N>, b: &$dvec<N>) -> N {
                 assert!(a.len() == b.len());
 
-                let mut res: N = Zero::zero();
+                let mut res: N = ::zero();
 
                 for i in range(0u, a.len()) {
                     res = res + unsafe { a.unsafe_at(i) * b.unsafe_at(i) };
diff --git a/src/structs/iso.rs b/src/structs/iso.rs
index b85d9040..3ee23e57 100644
--- a/src/structs/iso.rs
+++ b/src/structs/iso.rs
@@ -2,11 +2,10 @@
 
 #![allow(missing_docs)]
 
-use std::num::{Zero, One, Num};
 use std::rand::{Rand, Rng};
 use structs::mat::{Mat3, Mat4, Mat5};
-use traits::structure::{Cast, Dim, Col, BaseFloat};
-use traits::operations::{Inv, ApproxEq, Absolute};
+use traits::structure::{Cast, Dim, Col, BaseFloat, BaseNum, One};
+use traits::operations::{Inv, ApproxEq};
 use traits::geometry::{RotationMatrix, Rotation, Rotate, AbsoluteRotate, Transform, Transformation,
                        Translate, Translation, ToHomogeneous};
 
diff --git a/src/structs/iso_macros.rs b/src/structs/iso_macros.rs
index 9faa1097..50d83de4 100644
--- a/src/structs/iso_macros.rs
+++ b/src/structs/iso_macros.rs
@@ -2,7 +2,7 @@
 
 macro_rules! iso_impl(
     ($t: ident, $submat: ident, $subvec: ident, $subrotvec: ident) => (
-        impl<N: Clone + BaseFloat + Num> $t<N> {
+        impl<N: Clone + BaseFloat + BaseNum> $t<N> {
             /// Creates a new isometry from a rotation matrix and a vector.
             #[inline]
             pub fn new(translation: $subvec<N>, rotation: $subrotvec<N>) -> $t<N> {
@@ -26,7 +26,7 @@ macro_rules! iso_impl(
 
 macro_rules! rotation_matrix_impl(
     ($t: ident, $trot: ident, $tlv: ident, $tav: ident) => (
-        impl<N: Cast<f64> + BaseFloat + Num + Clone>
+        impl<N: Cast<f64> + BaseFloat + BaseNum + Clone>
         RotationMatrix<N, $tlv<N>, $tav<N>, $trot<N>> for $t<N> {
             #[inline]
             fn to_rot_mat(&self) -> $trot<N> {
@@ -53,7 +53,7 @@ macro_rules! one_impl(
         impl<N: BaseFloat + Clone> One for $t<N> {
             #[inline]
             fn one() -> $t<N> {
-                $t::new_with_rotmat(Zero::zero(), One::one())
+                $t::new_with_rotmat(::zero(), ::one())
             }
         }
     )
@@ -74,7 +74,7 @@ macro_rules! iso_mul_iso_impl(
 
 macro_rules! iso_mul_pnt_impl(
     ($t: ident, $tv: ident, $tmul: ident) => (
-        impl<N: Num + Clone> $tmul<N, $tv<N>> for $tv<N> {
+        impl<N: BaseNum + Clone> $tmul<N, $tv<N>> for $tv<N> {
             #[inline]
             fn binop(left: &$t<N>, right: &$tv<N>) -> $tv<N> {
                 left.rotation * *right + left.translation
@@ -85,7 +85,7 @@ macro_rules! iso_mul_pnt_impl(
 
 macro_rules! pnt_mul_iso_impl(
     ($t: ident, $tv: ident, $tmul: ident) => (
-        impl<N: Clone + Num> $tmul<N, $tv<N>> for $t<N> {
+        impl<N: Clone + BaseNum> $tmul<N, $tv<N>> for $t<N> {
             #[inline]
             fn binop(left: &$tv<N>, right: &$t<N>) -> $tv<N> {
                 (*left + right.translation) * right.rotation
@@ -204,7 +204,7 @@ macro_rules! rotation_impl(
 
 macro_rules! rotate_impl(
     ($t: ident, $tv: ident) => (
-        impl<N: Num + Clone> Rotate<$tv<N>> for $t<N> {
+        impl<N: BaseNum + Clone> Rotate<$tv<N>> for $t<N> {
             #[inline]
             fn rotate(&self, v: &$tv<N>) -> $tv<N> {
                 self.rotation.rotate(v)
@@ -276,7 +276,7 @@ macro_rules! transform_impl(
             }
         }
 
-        impl<N: Num + Clone> $trhs<N> for $tp<N> {
+        impl<N: BaseNum + Clone> $trhs<N> for $tp<N> {
             #[inline]
             fn transform(t: &$t<N>, p: &$tp<N>) -> $tp<N> {
                 t.rotation.transform(p) + t.translation
@@ -292,7 +292,7 @@ macro_rules! transform_impl(
 
 macro_rules! inv_impl(
     ($t: ident) => (
-        impl<N: Clone + Num> Inv for $t<N> {
+        impl<N: Clone + BaseNum> Inv for $t<N> {
             #[inline]
             fn inv(&mut self) -> bool {
                 self.rotation.inv();
@@ -317,7 +317,7 @@ macro_rules! inv_impl(
 
 macro_rules! to_homogeneous_impl(
     ($t: ident, $th: ident) => (
-        impl<N: Num + Clone> ToHomogeneous<$th<N>> for $t<N> {
+        impl<N: BaseNum + Clone> ToHomogeneous<$th<N>> for $t<N> {
             fn to_homogeneous(m: &$t<N>) -> $th<N> {
                 let mut res = ToHomogeneous::to_homogeneous(&m.rotation);
 
diff --git a/src/structs/lower_triangular.rs b/src/structs/lower_triangular.rs
deleted file mode 100644
index 787bfd3c..00000000
--- a/src/structs/lower_triangular.rs
+++ /dev/null
@@ -1,153 +0,0 @@
-use rand::Rand;
-use rand;
-use std::num::{One, Zero};
-use std::vec;
-
-/// A structure optimized to store lower triangular matrices.
-pub struct LowerTriangularMat<N> {
-    priv dim: uint,
-    priv mij: ~[N]
-}
-
-/// Trait to be implemented by objects which can be left-multiplied by a lower triangular array.
-pub trait LowerTriangularMatMulRhs<N, Res> {
-    /// Apply the muliplicitaion.
-    fn binop(left: &LowerTriangularMat<N>, right: &Self) -> Res;
-}
-
-impl<N, Rhs: LowerTriangularMatMulRhs<N, Res>, Res> Mul<Rhs, Res> for LowerTriangularMat<N> {
-    #[inline(always)]
-    fn mul(&self, other: &Rhs) -> Res {
-        LowerTriangularMatMulRhs::binop(self, other)
-    }
-}
-
-impl<N> LowerTriangularMat<N> {
-    /// Creates a lower triangular matrix without initializing its arguments.
-    #[inline]
-    pub unsafe fn new_uninitialized(dim: uint) -> LowerTriangularMat<N> {
-        let mut vec = vec::with_capacity(dim * (dim + 1) / 2);
-        vec::raw::set_len(&mut vec, dim * (dim + 1) / 2);
-
-        LowerTriangularMat {
-            dim: dim,
-            mij: vec
-        }
-    }
-}
-
-impl<N: Zero + Clone> LowerTriangularMat<N> {
-    /// Creates a lower triangular matrix filled with zeros.
-    #[inline]
-    pub fn new_zeros(dim: uint) -> LowerTriangularMat<N> {
-        LowerTriangularMat::from_elem(dim, Zero::zero())
-    }
-
-    /// Tests if every entry of the matrix are exactly zeros.
-    #[inline]
-    pub fn is_zero(&self) -> bool {
-        self.mij.iter().all(|e| e.is_zero())
-    }
-}
-
-impl<N: Rand> LowerTriangularMat<N> {
-    /// Creates a lower triangular matrix filled with random elements.
-    #[inline]
-    pub fn new_random(dim: uint) -> LowerTriangularMat<N> {
-        LowerTriangularMat::from_fn(dim, |_, _| rand::random())
-    }
-}
-
-impl<N: One + Clone> LowerTriangularMat<N> {
-    /// Creates a lower triangular matrix filled with ones.
-    #[inline]
-    pub fn new_ones(dim: uint) -> LowerTriangularMat<N> {
-        LowerTriangularMat::from_elem(dim, One::one())
-    }
-}
-
-impl<N: Clone> LowerTriangularMat<N> {
-    /// Creates a lower triangular matrix filled with a given value.
-    #[inline]
-    pub fn from_elem(dim: uint, val: N) -> LowerTriangularMat<N> {
-        LowerTriangularMat {
-            dim: dim,
-            mij: vec::from_elem(dim * (dim + 1) / 2, val)
-        }
-    }
-}
-
-impl<N> LowerTriangularMat<N> {
-    /// Creates a lower triangular matrix filled by a function.
-    #[inline(always)]
-    pub fn from_fn(dim: uint, f: &fn(uint, uint) -> N) -> LowerTriangularMat<N> {
-        let mij = do vec::from_fn(dim * (dim + 1) / 2) |i| {
-            let l = (((1.0f64 + 8.0f64 * i as f64).sqrt() - 1.) / 2.0f64).floor() as uint;
-            let c = i - l * (l + 1) / 2;
-
-            f(l, c)
-        };
-
-        LowerTriangularMat {
-            dim: dim,
-            mij: mij
-        }
-    }
-
-    #[inline]
-    fn offset(&self, i: uint, j: uint) -> uint {
-        i * (i + 1) / 2 + j + 1
-    }
-
-    /// Transforms this matrix into an array. This consumes the matrix and is O(1).
-    #[inline]
-    pub fn to_array(self) -> ~[N] {
-        self.mij
-    }
-}
-
-impl<N: Zero + Clone> LowerTriangularMat<N> {
-    /// Changes the value of a component of the matrix.
-    /// Fails if the indices point outside of the lower-triangular part of the matrix.
-    ///
-    /// # Arguments
-    ///   * `row` - 0-based index of the line to be changed
-    ///   * `col` - 0-based index of the column to be changed
-    #[inline]
-    pub fn set(&mut self, row: uint, col: uint, val: N) {
-        assert!(row < self.dim);
-        assert!(col < self.dim);
-        assert!(col <= row);
-        unsafe { self.set_fast(row, col, val) }
-    }
-
-    /// Just like `set` without bounds checking.
-    #[inline]
-    pub unsafe fn set_fast(&mut self, row: uint, col: uint, val: N) {
-        let offset = self.offset(row, col);
-        *self.mij.unsafe_mut_ref(offset) = val
-    }
-
-    /// Reads the value of a component of the matrix.
-    /// Fails if the indices point outside of the lower-triangular part of the matrix.
-    ///
-    /// # Arguments
-    ///   * `row` - 0-based index of the line to be read
-    ///   * `col` - 0-based index of the column to be read
-    #[inline]
-    pub fn at(&self, row: uint, col: uint) -> N {
-        assert!(row < self.dim);
-        assert!(col < self.dim);
-        unsafe { self.at_fast(row, col) }
-    }
-
-    /// Just like `at` without bounds checking.
-    #[inline]
-    pub unsafe fn at_fast(&self, row: uint, col: uint) -> N {
-        if col > row {
-            Zero::zero()
-        }
-
-        vec::raw::get(self.mij, self.offset(row, col))
-    }
-}
diff --git a/src/structs/mat.rs b/src/structs/mat.rs
index 66c44ea7..2e3539f1 100644
--- a/src/structs/mat.rs
+++ b/src/structs/mat.rs
@@ -3,7 +3,6 @@
 #![allow(missing_docs)] // we allow missing to avoid having to document the mij components.
 
 use std::mem;
-use std::num::{One, Zero, Num};
 use traits::operations::ApproxEq;
 use std::slice::{Items, MutItems};
 use structs::vec::{Vec1, Vec2, Vec3, Vec4, Vec5, Vec6,
@@ -12,7 +11,7 @@ use structs::pnt::{Pnt1, Pnt4, Pnt5, Pnt6, Pnt1MulRhs, Pnt4MulRhs, Pnt5MulRhs, P
 use structs::dvec::{DVec1, DVec2, DVec3, DVec4, DVec5, DVec6};
 
 use traits::structure::{Cast, Row, Col, Iterable, IterableMut, Dim, Indexable,
-                        Eye, ColSlice, RowSlice, Diag, Shape, BaseFloat};
+                        Eye, ColSlice, RowSlice, Diag, Shape, BaseFloat, BaseNum, Zero, One};
 use traits::operations::{Absolute, Transpose, Inv, Outer, EigenQR};
 use traits::geometry::{ToHomogeneous, FromHomogeneous, Orig};
 use linalg;
@@ -31,7 +30,7 @@ impl Identity {
 }
 
 /// Square matrix of dimension 1.
-#[deriving(Eq, PartialEq, Encodable, Decodable, Clone, Hash, Rand, Zero, Show)]
+#[deriving(Eq, PartialEq, Encodable, Decodable, Clone, Hash, Rand, Show)]
 pub struct Mat1<N> {
     pub m11: N
 }
@@ -106,7 +105,8 @@ mat_sub_scalar_impl!(Mat1, uint, Mat1SubRhs, m11)
 mat_sub_scalar_impl!(Mat1, int, Mat1SubRhs, m11)
 
 absolute_impl!(Mat1, m11)
-one_impl!(Mat1, One::one)
+zero_impl!(Mat1, m11)
+one_impl!(Mat1, ::one)
 iterable_impl!(Mat1, 1)
 iterable_mut_impl!(Mat1, 1)
 at_fast_impl!(Mat1, 1)
@@ -114,8 +114,8 @@ dim_impl!(Mat1, 1)
 indexable_impl!(Mat1, 1)
 index_impl!(Mat1, 1)
 mat_mul_mat_impl!(Mat1, Mat1MulRhs, 1)
-mat_mul_vec_impl!(Mat1, Vec1, Mat1MulRhs, 1, Zero::zero)
-vec_mul_mat_impl!(Mat1, Vec1, Vec1MulRhs, 1, Zero::zero)
+mat_mul_vec_impl!(Mat1, Vec1, Mat1MulRhs, 1, ::zero)
+vec_mul_mat_impl!(Mat1, Vec1, Vec1MulRhs, 1, ::zero)
 mat_mul_pnt_impl!(Mat1, Pnt1, Mat1MulRhs, 1, Orig::orig)
 pnt_mul_mat_impl!(Mat1, Pnt1, Pnt1MulRhs, 1, Orig::orig)
 // (specialized) inv_impl!(Mat1, 1)
@@ -132,7 +132,7 @@ outer_impl!(Vec1, Mat1)
 eigen_qr_impl!(Mat1, Vec1)
 
 /// Square matrix of dimension 2.
-#[deriving(Eq, PartialEq, Encodable, Decodable, Clone, Hash, Rand, Zero, Show)]
+#[deriving(Eq, PartialEq, Encodable, Decodable, Clone, Hash, Rand, Show)]
 pub struct Mat2<N> {
     pub m11: N, pub m21: N,
     pub m12: N, pub m22: N
@@ -211,8 +211,10 @@ mat_sub_scalar_impl!(Mat2, int, Mat2SubRhs, m11, m12, m21, m22)
 
 absolute_impl!(Mat2, m11, m12,
                      m21, m22)
-one_impl!(Mat2, One::one,   Zero::zero,
-                Zero::zero, One::one)
+zero_impl!(Mat2, m11, m12,
+                 m21, m22)
+one_impl!(Mat2, ::one,   ::zero,
+                ::zero, ::one)
 iterable_impl!(Mat2, 2)
 iterable_mut_impl!(Mat2, 2)
 dim_impl!(Mat2, 2)
@@ -236,7 +238,7 @@ outer_impl!(Vec2, Mat2)
 eigen_qr_impl!(Mat2, Vec2)
 
 /// Square matrix of dimension 3.
-#[deriving(Eq, PartialEq, Encodable, Decodable, Clone, Hash, Rand, Zero, Show)]
+#[deriving(Eq, PartialEq, Encodable, Decodable, Clone, Hash, Rand, Show)]
 pub struct Mat3<N> {
     pub m11: N, pub m21: N, pub m31: N,
     pub m12: N, pub m22: N, pub m32: N,
@@ -328,9 +330,14 @@ absolute_impl!(Mat3,
     m21, m22, m23,
     m31, m32, m33
 )
-one_impl!(Mat3, One::one  , Zero::zero, Zero::zero,
-                Zero::zero, One::one  , Zero::zero,
-                Zero::zero, Zero::zero, One::one)
+zero_impl!(Mat3,
+    m11, m12, m13,
+    m21, m22, m23,
+    m31, m32, m33
+)
+one_impl!(Mat3, ::one  , ::zero, ::zero,
+                ::zero, ::one  , ::zero,
+                ::zero, ::zero, ::one)
 iterable_impl!(Mat3, 3)
 iterable_mut_impl!(Mat3, 3)
 dim_impl!(Mat3, 3)
@@ -354,7 +361,7 @@ outer_impl!(Vec3, Mat3)
 eigen_qr_impl!(Mat3, Vec3)
 
 /// Square matrix of dimension 4.
-#[deriving(Eq, PartialEq, Encodable, Decodable, Clone, Hash, Rand, Zero, Show)]
+#[deriving(Eq, PartialEq, Encodable, Decodable, Clone, Hash, Rand, Show)]
 pub struct Mat4<N> {
     pub m11: N, pub m21: N, pub m31: N, pub m41: N,
     pub m12: N, pub m22: N, pub m32: N, pub m42: N,
@@ -497,10 +504,16 @@ absolute_impl!(Mat4,
   m31, m32, m33, m34,
   m41, m42, m43, m44
 )
-one_impl!(Mat4, One::one  , Zero::zero, Zero::zero, Zero::zero,
-                Zero::zero, One::one  , Zero::zero, Zero::zero,
-                Zero::zero, Zero::zero, One::one  , Zero::zero,
-                Zero::zero, Zero::zero, Zero::zero, One::one)
+zero_impl!(Mat4,
+  m11, m12, m13, m14,
+  m21, m22, m23, m24,
+  m31, m32, m33, m34,
+  m41, m42, m43, m44
+)
+one_impl!(Mat4, ::one  , ::zero, ::zero, ::zero,
+                ::zero, ::one  , ::zero, ::zero,
+                ::zero, ::zero, ::one  , ::zero,
+                ::zero, ::zero, ::zero, ::one)
 iterable_impl!(Mat4, 4)
 iterable_mut_impl!(Mat4, 4)
 dim_impl!(Mat4, 4)
@@ -508,8 +521,8 @@ indexable_impl!(Mat4, 4)
 index_impl!(Mat4, 4)
 at_fast_impl!(Mat4, 4)
 mat_mul_mat_impl!(Mat4, Mat4MulRhs, 4)
-mat_mul_vec_impl!(Mat4, Vec4, Mat4MulRhs, 4, Zero::zero)
-vec_mul_mat_impl!(Mat4, Vec4, Vec4MulRhs, 4, Zero::zero)
+mat_mul_vec_impl!(Mat4, Vec4, Mat4MulRhs, 4, ::zero)
+vec_mul_mat_impl!(Mat4, Vec4, Vec4MulRhs, 4, ::zero)
 mat_mul_pnt_impl!(Mat4, Pnt4, Mat4MulRhs, 4, Orig::orig)
 pnt_mul_mat_impl!(Mat4, Pnt4, Pnt4MulRhs, 4, Orig::orig)
 inv_impl!(Mat4, 4)
@@ -526,7 +539,7 @@ outer_impl!(Vec4, Mat4)
 eigen_qr_impl!(Mat4, Vec4)
 
 /// Square matrix of dimension 5.
-#[deriving(Eq, PartialEq, Encodable, Decodable, Clone, Hash, Rand, Zero, Show)]
+#[deriving(Eq, PartialEq, Encodable, Decodable, Clone, Hash, Rand, Show)]
 pub struct Mat5<N> {
     pub m11: N, pub m21: N, pub m31: N, pub m41: N, pub m51: N,
     pub m12: N, pub m22: N, pub m32: N, pub m42: N, pub m52: N,
@@ -568,12 +581,19 @@ absolute_impl!(Mat5,
   m41, m42, m43, m44, m45,
   m51, m52, m53, m54, m55
 )
+zero_impl!(Mat5,
+  m11, m12, m13, m14, m15,
+  m21, m22, m23, m24, m25,
+  m31, m32, m33, m34, m35,
+  m41, m42, m43, m44, m45,
+  m51, m52, m53, m54, m55
+)
 one_impl!(Mat5,
-  One::one  , Zero::zero, Zero::zero, Zero::zero, Zero::zero,
-  Zero::zero, One::one  , Zero::zero, Zero::zero, Zero::zero,
-  Zero::zero, Zero::zero, One::one  , Zero::zero, Zero::zero,
-  Zero::zero, Zero::zero, Zero::zero, One::one  , Zero::zero,
-  Zero::zero, Zero::zero, Zero::zero, Zero::zero, One::one
+  ::one  , ::zero, ::zero, ::zero, ::zero,
+  ::zero, ::one  , ::zero, ::zero, ::zero,
+  ::zero, ::zero, ::one  , ::zero, ::zero,
+  ::zero, ::zero, ::zero, ::one  , ::zero,
+  ::zero, ::zero, ::zero, ::zero, ::one
 )
 add_impl!(Mat5, Mat5AddRhs,
   m11, m12, m13, m14, m15,
@@ -696,8 +716,8 @@ indexable_impl!(Mat5, 5)
 index_impl!(Mat5, 5)
 at_fast_impl!(Mat5, 5)
 mat_mul_mat_impl!(Mat5, Mat5MulRhs, 5)
-mat_mul_vec_impl!(Mat5, Vec5, Mat5MulRhs, 5, Zero::zero)
-vec_mul_mat_impl!(Mat5, Vec5, Vec5MulRhs, 5, Zero::zero)
+mat_mul_vec_impl!(Mat5, Vec5, Mat5MulRhs, 5, ::zero)
+vec_mul_mat_impl!(Mat5, Vec5, Vec5MulRhs, 5, ::zero)
 mat_mul_pnt_impl!(Mat5, Pnt5, Mat5MulRhs, 5, Orig::orig)
 pnt_mul_mat_impl!(Mat5, Pnt5, Pnt5MulRhs, 5, Orig::orig)
 inv_impl!(Mat5, 5)
@@ -714,7 +734,7 @@ outer_impl!(Vec5, Mat5)
 eigen_qr_impl!(Mat5, Vec5)
 
 /// Square matrix of dimension 6.
-#[deriving(Eq, PartialEq, Encodable, Decodable, Clone, Hash, Rand, Zero, Show)]
+#[deriving(Eq, PartialEq, Encodable, Decodable, Clone, Hash, Rand, Show)]
 pub struct Mat6<N> {
     pub m11: N, pub m21: N, pub m31: N, pub m41: N, pub m51: N, pub m61: N,
     pub m12: N, pub m22: N, pub m32: N, pub m42: N, pub m52: N, pub m62: N,
@@ -921,13 +941,17 @@ absolute_impl!(Mat6, m11, m12, m13, m14, m15, m16, m21, m22, m23, m24, m25, m26,
   m31, m32, m33, m34, m35, m36, m41, m42, m43, m44, m45, m46, m51, m52, m53, m54, m55, m56,
   m61, m62, m63, m64, m65, m66)
 
+zero_impl!(Mat6, m11, m12, m13, m14, m15, m16, m21, m22, m23, m24, m25, m26,
+  m31, m32, m33, m34, m35, m36, m41, m42, m43, m44, m45, m46, m51, m52, m53, m54, m55, m56,
+  m61, m62, m63, m64, m65, m66)
+
 one_impl!(Mat6,
-  One::one  , Zero::zero, Zero::zero, Zero::zero, Zero::zero, Zero::zero,
-  Zero::zero, One::one  , Zero::zero, Zero::zero, Zero::zero, Zero::zero,
-  Zero::zero, Zero::zero, One::one  , Zero::zero, Zero::zero, Zero::zero,
-  Zero::zero, Zero::zero, Zero::zero, One::one  , Zero::zero, Zero::zero,
-  Zero::zero, Zero::zero, Zero::zero, Zero::zero, One::one  , Zero::zero,
-  Zero::zero, Zero::zero, Zero::zero, Zero::zero, Zero::zero, One::one
+  ::one  , ::zero, ::zero, ::zero, ::zero, ::zero,
+  ::zero, ::one  , ::zero, ::zero, ::zero, ::zero,
+  ::zero, ::zero, ::one  , ::zero, ::zero, ::zero,
+  ::zero, ::zero, ::zero, ::one  , ::zero, ::zero,
+  ::zero, ::zero, ::zero, ::zero, ::one  , ::zero,
+  ::zero, ::zero, ::zero, ::zero, ::zero, ::one
 )
 iterable_impl!(Mat6, 6)
 iterable_mut_impl!(Mat6, 6)
@@ -936,8 +960,8 @@ indexable_impl!(Mat6, 6)
 index_impl!(Mat6, 6)
 at_fast_impl!(Mat6, 6)
 mat_mul_mat_impl!(Mat6, Mat6MulRhs, 6)
-mat_mul_vec_impl!(Mat6, Vec6, Mat6MulRhs, 6, Zero::zero)
-vec_mul_mat_impl!(Mat6, Vec6, Vec6MulRhs, 6, Zero::zero)
+mat_mul_vec_impl!(Mat6, Vec6, Mat6MulRhs, 6, ::zero)
+vec_mul_mat_impl!(Mat6, Vec6, Vec6MulRhs, 6, ::zero)
 mat_mul_pnt_impl!(Mat6, Pnt6, Mat6MulRhs, 6, Orig::orig)
 pnt_mul_mat_impl!(Mat6, Pnt6, Pnt6MulRhs, 6, Orig::orig)
 inv_impl!(Mat6, 6)
diff --git a/src/structs/mat_macros.rs b/src/structs/mat_macros.rs
index e2d6afcf..960fdc2d 100644
--- a/src/structs/mat_macros.rs
+++ b/src/structs/mat_macros.rs
@@ -104,8 +104,8 @@ macro_rules! eye_impl(
         impl<N: Zero + One> Eye for $t<N> {
             fn new_identity(dim: uint) -> $t<N> {
                 assert!(dim == $ndim);
-                let mut eye: $t<N> = Zero::zero();
-                $(eye.$comp_diagN = One::one();)+
+                let mut eye: $t<N> = ::zero();
+                $(eye.$comp_diagN = ::one();)+
                 eye
             }
         }
@@ -162,7 +162,7 @@ macro_rules! iterable_mut_impl(
 
 macro_rules! one_impl(
   ($t: ident, $value0: expr $(, $valueN: expr)* ) => (
-    impl<N: Clone + Num> One for $t<N> {
+    impl<N: Clone + BaseNum> One for $t<N> {
         #[inline]
         fn one() -> $t<N> {
             $t::new($value0() $(, $valueN() )*)
@@ -171,6 +171,25 @@ macro_rules! one_impl(
   )
 )
 
+macro_rules! zero_impl(
+  ($t: ident, $comp0: ident $(, $compN: ident)* ) => (
+    impl<N: Zero> Zero for $t<N> {
+        #[inline]
+        fn zero() -> $t<N> {
+            $t {
+                $comp0: ::zero()
+                $(, $compN: ::zero() )*
+            }
+        }
+
+        #[inline]
+        fn is_zero(&self) -> bool {
+            ::is_zero(&self.$comp0) $(&& ::is_zero(&self.$compN) )*
+        }
+    }
+  )
+)
+
 macro_rules! dim_impl(
   ($t: ident, $dim: expr) => (
     impl<N> Dim for $t<N> {
@@ -276,7 +295,7 @@ macro_rules! row_impl(
 
         #[inline]
         fn row(&self, row: uint) -> $tv<N> {
-            let mut res: $tv<N> = Zero::zero();
+            let mut res: $tv<N> = ::zero();
 
             for (i, e) in res.iter_mut().enumerate() {
                 *e = self.at((row, i));
@@ -317,7 +336,7 @@ macro_rules! col_impl(
 
         #[inline]
         fn col(&self, col: uint) -> $tv<N> {
-            let mut res: $tv<N> = Zero::zero();
+            let mut res: $tv<N> = ::zero();
 
             for (i, e) in res.iter_mut().enumerate() {
                 *e = self.at((i, col));
@@ -334,7 +353,7 @@ macro_rules! diag_impl(
         impl<N: Clone + Zero> Diag<$tv<N>> for $t<N> {
             #[inline]
             fn from_diag(diag: &$tv<N>) -> $t<N> {
-                let mut res: $t<N> = Zero::zero();
+                let mut res: $t<N> = ::zero();
 
                 res.set_diag(diag);
 
@@ -350,7 +369,7 @@ macro_rules! diag_impl(
 
             #[inline]
             fn diag(&self) -> $tv<N> {
-                let mut diag: $tv<N> = Zero::zero();
+                let mut diag: $tv<N> = ::zero();
 
                 for i in range(0, $dim) {
                     unsafe { diag.unsafe_set(i, self.unsafe_at((i, i))) }
@@ -364,15 +383,15 @@ macro_rules! diag_impl(
 
 macro_rules! mat_mul_mat_impl(
   ($t: ident, $trhs: ident, $dim: expr) => (
-    impl<N: Clone + Num> $trhs<N, $t<N>> for $t<N> {
+    impl<N: Clone + BaseNum> $trhs<N, $t<N>> for $t<N> {
         #[inline]
         fn binop(left: &$t<N>, right: &$t<N>) -> $t<N> {
             // careful! we need to comute other * self here (self is the rhs).
-            let mut res: $t<N> = Zero::zero();
+            let mut res: $t<N> = ::zero();
 
             for i in range(0u, $dim) {
                 for j in range(0u, $dim) {
-                    let mut acc: N = Zero::zero();
+                    let mut acc: N = ::zero();
 
                     unsafe {
                         for k in range(0u, $dim) {
@@ -392,7 +411,7 @@ macro_rules! mat_mul_mat_impl(
 
 macro_rules! vec_mul_mat_impl(
   ($t: ident, $v: ident, $trhs: ident, $dim: expr, $zero: expr) => (
-    impl<N: Clone + Num> $trhs<N, $v<N>> for $t<N> {
+    impl<N: Clone + BaseNum> $trhs<N, $v<N>> for $t<N> {
         #[inline]
         fn binop(left: &$v<N>, right: &$t<N>) -> $v<N> {
             let mut res : $v<N> = $zero();
@@ -414,7 +433,7 @@ macro_rules! vec_mul_mat_impl(
 
 macro_rules! mat_mul_vec_impl(
   ($t: ident, $v: ident, $trhs: ident, $dim: expr, $zero: expr) => (
-    impl<N: Clone + Num> $trhs<N, $v<N>> for $v<N> {
+    impl<N: Clone + BaseNum> $trhs<N, $v<N>> for $v<N> {
         #[inline]
         fn binop(left: &$t<N>, right: &$v<N>) -> $v<N> {
             let mut res : $v<N> = $zero();
@@ -448,7 +467,7 @@ macro_rules! mat_mul_pnt_impl(
 
 macro_rules! inv_impl(
   ($t: ident, $dim: expr) => (
-    impl<N: Clone + Num>
+    impl<N: Clone + BaseNum>
     Inv for $t<N> {
         #[inline]
         fn inv_cpy(m: &$t<N>) -> Option<$t<N>> {
@@ -463,7 +482,7 @@ macro_rules! inv_impl(
         }
 
         fn inv(&mut self) -> bool {
-            let mut res: $t<N> = One::one();
+            let mut res: $t<N> = ::one();
 
             // inversion using Gauss-Jordan elimination
             for k in range(0u, $dim) {
@@ -474,7 +493,7 @@ macro_rules! inv_impl(
                 let mut n0 = k; // index of a non-zero entry
 
                 while n0 != $dim {
-                    if self.at((n0, k)) != Zero::zero() {
+                    if self.at((n0, k)) != ::zero() {
                         break;
                     }
 
@@ -581,10 +600,10 @@ macro_rules! approx_eq_impl(
 
 macro_rules! to_homogeneous_impl(
   ($t: ident, $t2: ident, $dim: expr, $dim2: expr) => (
-    impl<N: Num + Clone> ToHomogeneous<$t2<N>> for $t<N> {
+    impl<N: BaseNum + Clone> ToHomogeneous<$t2<N>> for $t<N> {
         #[inline]
         fn to_homogeneous(m: &$t<N>) -> $t2<N> {
-            let mut res: $t2<N> = One::one();
+            let mut res: $t2<N> = ::one();
 
             for i in range(0u, $dim) {
                 for j in range(0u, $dim) {
@@ -600,10 +619,10 @@ macro_rules! to_homogeneous_impl(
 
 macro_rules! from_homogeneous_impl(
   ($t: ident, $t2: ident, $dim: expr, $dim2: expr) => (
-    impl<N: Num + Clone> FromHomogeneous<$t2<N>> for $t<N> {
+    impl<N: BaseNum + Clone> FromHomogeneous<$t2<N>> for $t<N> {
         #[inline]
         fn from(m: &$t2<N>) -> $t<N> {
-            let mut res: $t<N> = One::one();
+            let mut res: $t<N> = ::one();
 
             for i in range(0u, $dim2) {
                 for j in range(0u, $dim2) {
@@ -625,7 +644,7 @@ macro_rules! outer_impl(
         impl<N: Clone + Mul<N, N> + Zero> Outer<$m<N>> for $t<N> {
             #[inline]
             fn outer(a: &$t<N>, b: &$t<N>) -> $m<N> {
-                let mut res: $m<N> = Zero::zero();
+                let mut res: $m<N> = ::zero();
 
                 for i in range(0u, Dim::dim(None::<$t<N>>)) {
                     for j in range(0u, Dim::dim(None::<$t<N>>)) {
@@ -642,7 +661,7 @@ macro_rules! outer_impl(
 macro_rules! eigen_qr_impl(
     ($t: ident, $v: ident) => (
         impl<N> EigenQR<N, $v<N>> for $t<N>
-            where N: Num + One + Zero + BaseFloat + ApproxEq<N> + Clone {
+            where N: BaseNum + One + Zero + BaseFloat + ApproxEq<N> + Clone {
             fn eigen_qr(m: &$t<N>, eps: &N, niter: uint) -> ($t<N>, $v<N>) {
                 linalg::eigen_qr(m, eps, niter)
             }
diff --git a/src/structs/ortho.rs b/src/structs/ortho.rs
index e92bee6a..01941ce4 100644
--- a/src/structs/ortho.rs
+++ b/src/structs/ortho.rs
@@ -1,4 +1,3 @@
-use std::num::{Zero, One };
 use std::num;
 use traits::structure::BaseFloat;
 use structs::{Pnt3, Vec3, Mat4};
@@ -25,9 +24,9 @@ pub struct OrthoMat3<N> {
 impl<N: BaseFloat> Ortho3<N> {
     /// Creates a new 3D orthographic projection.
     pub fn new(width: N, height: N, znear: N, zfar: N) -> Ortho3<N> {
-        assert!(!(zfar - znear).is_zero());
-        assert!(!width.is_zero());
-        assert!(!height.is_zero());
+        assert!(!::is_zero(&(zfar - znear)));
+        assert!(!::is_zero(&width));
+        assert!(!::is_zero(&height));
 
         Ortho3 {
             width:  width,
@@ -115,11 +114,11 @@ impl<N: BaseFloat + Clone> Ortho3<N> {
 impl<N: BaseFloat> OrthoMat3<N> {
     /// Creates a new orthographic projection matrix from the width, heihgt, znear and zfar planes of the view cuboid.
     pub fn new(width: N, height: N, znear: N, zfar: N) -> OrthoMat3<N> {
-        assert!(!(zfar - znear).is_zero());
-        assert!(!width.is_zero());
-        assert!(!height.is_zero());
+        assert!(!::is_zero(&(zfar - znear)));
+        assert!(!::is_zero(&width));
+        assert!(!::is_zero(&height));
 
-        let mat: Mat4<N> = One::one();
+        let mat: Mat4<N> = ::one();
 
         let mut res = OrthoMat3 { mat: mat };
         res.set_width(width);
@@ -160,26 +159,26 @@ impl<N: BaseFloat> OrthoMat3<N> {
     /// The near plane offset of the view cuboid.
     #[inline]
     pub fn znear(&self) -> N {
-        (self.mat.m34 + One::one()) / self.mat.m33
+        (self.mat.m34 + ::one()) / self.mat.m33
     }
 
     /// The far plane offset of the view cuboid.
     #[inline]
     pub fn zfar(&self) -> N {
-        (self.mat.m34 - One::one()) / self.mat.m33
+        (self.mat.m34 - ::one()) / self.mat.m33
     }
 
     /// Sets the width of the view cuboid.
     #[inline]
     pub fn set_width(&mut self, width: N) {
-        assert!(!width.is_zero());
+        assert!(!::is_zero(&width));
         self.mat.m11 = num::cast::<f64, N>(2.0).unwrap() / width;
     }
 
     /// Sets the height of the view cuboid.
     #[inline]
     pub fn set_height(&mut self, height: N) {
-        assert!(!height.is_zero());
+        assert!(!::is_zero(&height));
         self.mat.m22 = num::cast::<f64, N>(2.0).unwrap() / height;
     }
 
@@ -200,7 +199,7 @@ impl<N: BaseFloat> OrthoMat3<N> {
     /// Sets the near and far plane offsets of the view cuboid.
     #[inline]
     pub fn set_znear_and_zfar(&mut self, znear: N, zfar: N) {
-        assert!(!(zfar - znear).is_zero());
+        assert!(!::is_zero(&(zfar - znear)));
         self.mat.m33 = -num::cast::<f64, N>(2.0).unwrap() / (zfar - znear);
         self.mat.m34 = -(zfar + znear) / (zfar - znear);
     }
diff --git a/src/structs/persp.rs b/src/structs/persp.rs
index df829577..0b420270 100644
--- a/src/structs/persp.rs
+++ b/src/structs/persp.rs
@@ -1,4 +1,3 @@
-use std::num::{Zero, One};
 use traits::structure::BaseFloat;
 use structs::{Pnt3, Vec3, Mat4};
 
@@ -24,8 +23,8 @@ pub struct PerspMat3<N> {
 impl<N: BaseFloat> Persp3<N> {
     /// Creates a new 3D perspective projection.
     pub fn new(aspect: N, fov: N, znear: N, zfar: N) -> Persp3<N> {
-        assert!(!(zfar - znear).is_zero());
-        assert!(!aspect.is_zero());
+        assert!(!::is_zero(&(zfar - znear)));
+        assert!(!::is_zero(&aspect));
 
         Persp3 {
             aspect: aspect,
@@ -121,17 +120,17 @@ impl<N: BaseFloat + Clone> Persp3<N> {
 impl<N: BaseFloat> PerspMat3<N> {
     /// Creates a new persepctive matrix from the aspect ratio, field of view, and near/far planes.
     pub fn new(aspect: N, fov: N, znear: N, zfar: N) -> PerspMat3<N> {
-        assert!(!(znear - zfar).is_zero());
-        assert!(!aspect.is_zero());
+        assert!(!::is_zero(&(znear - zfar)));
+        assert!(!::is_zero(&aspect));
 
-        let mat: Mat4<N> = One::one();
+        let mat: Mat4<N> = ::one();
 
         let mut res = PerspMat3 { mat: mat };
         res.set_fov(fov);
         res.set_aspect(aspect);
         res.set_znear_and_zfar(znear, zfar);
-        res.mat.m44 = Zero::zero();
-        res.mat.m43 = One::one();
+        res.mat.m44 = ::zero();
+        res.mat.m43 = ::one();
 
         res
     }
@@ -161,7 +160,7 @@ impl<N: BaseFloat> PerspMat3<N> {
     /// Gets the field of view of the view frustrum.
     #[inline]
     pub fn fov(&self) -> N {
-        let _1: N = One::one();
+        let _1: N = ::one();
         let _2 = _1 + _1;
 
         (_1 / self.mat.m22).atan() * _2
@@ -170,7 +169,7 @@ impl<N: BaseFloat> PerspMat3<N> {
     /// Gets the near plane offset of the view frustrum.
     #[inline]
     pub fn znear(&self) -> N {
-        let _1: N = One::one();
+        let _1: N = ::one();
         let _2 = _1 + _1;
         let ratio = (self.mat.m33 + _1) / (self.mat.m33 - _1);
 
@@ -180,7 +179,7 @@ impl<N: BaseFloat> PerspMat3<N> {
     /// Gets the far plane offset of the view frustrum.
     #[inline]
     pub fn zfar(&self) -> N {
-        let _1: N = One::one();
+        let _1: N = ::one();
         let _2 = _1 + _1;
         let ratio = (self.mat.m33 + _1) / (self.mat.m33 - _1);
 
@@ -193,14 +192,14 @@ impl<N: BaseFloat> PerspMat3<N> {
     /// frustrum.
     #[inline]
     pub fn set_aspect(&mut self, aspect: N) {
-        assert!(!aspect.is_zero());
+        assert!(!::is_zero(&aspect));
         self.mat.m11 = -self.mat.m22 / aspect;
     }
 
     /// Updates this projection with a new field of view of the view frustrum.
     #[inline]
     pub fn set_fov(&mut self, fov: N) {
-        let _1: N = One::one();
+        let _1: N = ::one();
         let _2 = _1 + _1;
 
         let old_m22  = self.mat.m22.clone();
@@ -225,7 +224,7 @@ impl<N: BaseFloat> PerspMat3<N> {
     /// Updates this projection matrix with new near and far plane offsets of the view frustrum.
     #[inline]
     pub fn set_znear_and_zfar(&mut self, znear: N, zfar: N) {
-        let _1: N = One::one();
+        let _1: N = ::one();
         let _2 = _1 + _1;
 
         self.mat.m33 = -(zfar + znear) / (znear - zfar);
@@ -235,7 +234,7 @@ impl<N: BaseFloat> PerspMat3<N> {
     /// Projects a point.
     #[inline]
     pub fn project_pnt(&self, p: &Pnt3<N>) -> Pnt3<N> {
-        let _1: N = One::one();
+        let _1: N = ::one();
         let inv_denom = _1 / p.z;
         Pnt3::new(
             self.mat.m11 * p.x * inv_denom,
@@ -247,7 +246,7 @@ impl<N: BaseFloat> PerspMat3<N> {
     /// Projects a vector.
     #[inline]
     pub fn project_vec(&self, p: &Vec3<N>) -> Vec3<N> {
-        let _1: N = One::one();
+        let _1: N = ::one();
         let inv_denom = _1 / p.z;
         Vec3::new(
             self.mat.m11 * p.x * inv_denom,
diff --git a/src/structs/pnt.rs b/src/structs/pnt.rs
index bc90eb83..51761d8b 100644
--- a/src/structs/pnt.rs
+++ b/src/structs/pnt.rs
@@ -3,14 +3,13 @@
 #![allow(missing_docs)] // we allow missing to avoid having to document the point components.
 
 use std::mem;
-use std::num::{Zero, One, Bounded, Num};
 use std::slice::{Items, MutItems};
 use std::iter::{Iterator, FromIterator};
 use traits::operations::{ApproxEq, POrd, POrdering, PartialLess, PartialEqual,
                          PartialGreater, NotComparable, Axpy, ScalarAdd, ScalarSub, ScalarMul,
                          ScalarDiv};
 use traits::structure::{Cast, Dim, Indexable, Iterable, IterableMut, PntAsVec, Shape,
-                        NumPnt, FloatPnt, BaseFloat};
+                        NumPnt, FloatPnt, BaseFloat, BaseNum, Zero, One, Bounded};
 use traits::geometry::{Orig, FromHomogeneous, ToHomogeneous};
 use structs::vec::{Vec1, Vec2, Vec3, Vec4, Vec5, Vec6};
 
diff --git a/src/structs/pnt_macros.rs b/src/structs/pnt_macros.rs
index d8ef262b..fc10fce3 100644
--- a/src/structs/pnt_macros.rs
+++ b/src/structs/pnt_macros.rs
@@ -6,8 +6,8 @@ macro_rules! orig_impl(
             #[inline]
             fn orig() -> $t<N> {
                 $t {
-                    $comp0: Zero::zero()
-                    $(, $compN: Zero::zero() )*
+                    $comp0: ::zero()
+                    $(, $compN: ::zero() )*
                 }
             }
 
@@ -106,7 +106,7 @@ macro_rules! pnt_to_homogeneous_impl(
 
                 res.$comp0    = v.$comp0.clone();
                 $( res.$compN = v.$compN.clone(); )*
-                res.$extra    = One::one();
+                res.$extra    = ::one();
 
                 res
             }
@@ -132,11 +132,11 @@ macro_rules! pnt_from_homogeneous_impl(
 macro_rules! num_float_pnt_impl(
     ($t: ident, $tv: ident $(,$trhs: ident)*) => (
         impl<N> NumPnt<N, $tv<N>> for $t<N>
-            where N: Num $(+ $trhs<N, $t<N>>)* {
+            where N: BaseNum + Zero $(+ $trhs<N, $t<N>>)* {
         }
 
         impl<N> FloatPnt<N, $tv<N>> for $t<N>
-            where N: Num + One + Zero + ApproxEq<N> + BaseFloat $(+ $trhs<N, $t<N>>)* {
+            where N: BaseNum + One + Zero + ApproxEq<N> + BaseFloat $(+ $trhs<N, $t<N>>)* {
         }
     )
 )
diff --git a/src/structs/quat.rs b/src/structs/quat.rs
index 5e1d03af..bdd4bd6d 100644
--- a/src/structs/quat.rs
+++ b/src/structs/quat.rs
@@ -3,7 +3,6 @@
 #![allow(missing_docs)] // we allow missing to avoid having to document the dispatch trait.
 
 use std::mem;
-use std::num::{Zero, One, Bounded, Num};
 use std::num;
 use std::rand::{Rand, Rng};
 use std::slice::{Items, MutItems};
@@ -11,11 +10,12 @@ use structs::{Vec3, Pnt3, Rot3, Mat3, Vec3MulRhs, Pnt3MulRhs};
 use traits::operations::{ApproxEq, Inv, POrd, POrdering, NotComparable, PartialLess,
                          PartialGreater, PartialEqual, Axpy, ScalarAdd, ScalarSub, ScalarMul,
                          ScalarDiv};
-use traits::structure::{Cast, Indexable, Iterable, IterableMut, Dim, Shape, BaseFloat};
+use traits::structure::{Cast, Indexable, Iterable, IterableMut, Dim, Shape, BaseFloat, BaseNum, Zero,
+                        One, Bounded};
 use traits::geometry::{Norm, Cross, Rotation, Rotate, Transform};
 
 /// A quaternion.
-#[deriving(Eq, PartialEq, Encodable, Decodable, Clone, Hash, Rand, Zero, Show)]
+#[deriving(Eq, PartialEq, Encodable, Decodable, Clone, Hash, Rand, Show)]
 pub struct Quat<N> {
     /// The scalar component of the quaternion.
     pub w: N,
@@ -82,7 +82,7 @@ impl<N: BaseFloat + ApproxEq<N> + Clone> Inv for Quat<N> {
     fn inv(&mut self) -> bool {
         let sqnorm = Norm::sqnorm(self);
 
-        if ApproxEq::approx_eq(&sqnorm, &Zero::zero()) {
+        if ApproxEq::approx_eq(&sqnorm, &::zero()) {
             false
         }
         else {
@@ -152,8 +152,8 @@ impl<N: BaseFloat> UnitQuat<N> {
     pub fn new(axisangle: Vec3<N>) -> UnitQuat<N> {
         let sqang = Norm::sqnorm(&axisangle);
 
-        if sqang.is_zero() {
-            One::one()
+        if ::is_zero(&sqang) {
+            ::one()
         }
         else {
             let ang    = sqang.sqrt();
@@ -251,11 +251,11 @@ impl<N> UnitQuat<N> {
     }
 }
 
-impl<N: Num + Clone> One for UnitQuat<N> {
+impl<N: BaseNum + Clone> One for UnitQuat<N> {
     #[inline]
     fn one() -> UnitQuat<N> {
         unsafe {
-            UnitQuat::new_with_unit_quat(Quat::new(One::one(), Zero::zero(), Zero::zero(), Zero::zero()))
+            UnitQuat::new_with_unit_quat(Quat::new(::one(), ::zero(), ::zero(), ::zero()))
         }
     }
 }
@@ -308,17 +308,17 @@ impl<N: BaseFloat + ApproxEq<N> + Clone> Div<UnitQuat<N>, UnitQuat<N>> for UnitQ
     }
 }
 
-impl<N: Num + Clone> UnitQuatMulRhs<N, UnitQuat<N>> for UnitQuat<N> {
+impl<N: BaseNum + Clone> UnitQuatMulRhs<N, UnitQuat<N>> for UnitQuat<N> {
     #[inline]
     fn binop(left: &UnitQuat<N>, right: &UnitQuat<N>) -> UnitQuat<N> {
         UnitQuat { q: left.q * right.q }
     }
 }
 
-impl<N: Num + Clone> UnitQuatMulRhs<N, Vec3<N>> for Vec3<N> {
+impl<N: BaseNum + Clone> UnitQuatMulRhs<N, Vec3<N>> for Vec3<N> {
     #[inline]
     fn binop(left: &UnitQuat<N>, right: &Vec3<N>) -> Vec3<N> {
-        let _2: N = num::one::<N>() + num::one();
+        let _2: N = ::one::<N>() + ::one();
         let mut t = Cross::cross(left.q.vector(), right);
         t.x = t.x * _2;
         t.y = t.y * _2;
@@ -330,14 +330,14 @@ impl<N: Num + Clone> UnitQuatMulRhs<N, Vec3<N>> for Vec3<N> {
     }
 }
 
-impl<N: Num + Clone> UnitQuatMulRhs<N, Pnt3<N>> for Pnt3<N> {
+impl<N: BaseNum + Clone> UnitQuatMulRhs<N, Pnt3<N>> for Pnt3<N> {
     #[inline]
     fn binop(left: &UnitQuat<N>, right: &Pnt3<N>) -> Pnt3<N> {
         ::orig::<Pnt3<N>>() + *left * *right.as_vec()
     }
 }
 
-impl<N: Num + Clone> Vec3MulRhs<N, Vec3<N>> for UnitQuat<N> {
+impl<N: BaseNum + Clone> Vec3MulRhs<N, Vec3<N>> for UnitQuat<N> {
     #[inline]
     fn binop(left: &Vec3<N>, right: &UnitQuat<N>) -> Vec3<N> {
         let mut inv_quat = right.clone();
@@ -347,7 +347,7 @@ impl<N: Num + Clone> Vec3MulRhs<N, Vec3<N>> for UnitQuat<N> {
     }
 }
 
-impl<N: Num + Clone> Pnt3MulRhs<N, Pnt3<N>> for UnitQuat<N> {
+impl<N: BaseNum + Clone> Pnt3MulRhs<N, Pnt3<N>> for UnitQuat<N> {
     #[inline]
     fn binop(left: &Pnt3<N>, right: &UnitQuat<N>) -> Pnt3<N> {
         ::orig::<Pnt3<N>>() + *left.as_vec() * *right
@@ -357,12 +357,12 @@ impl<N: Num + Clone> Pnt3MulRhs<N, Pnt3<N>> for UnitQuat<N> {
 impl<N: BaseFloat + Clone> Rotation<Vec3<N>> for UnitQuat<N> {
     #[inline]
     fn rotation(&self) -> Vec3<N> {
-        let _2 = num::one::<N>() + num::one();
+        let _2 = ::one::<N>() + ::one();
         let mut v = self.q.vector().clone();
         let ang = _2 * v.normalize().atan2(self.q.w);
 
-        if ang.is_zero() {
-            num::zero()
+        if ::is_zero(&ang) {
+            ::zero()
         }
         else {
             Vec3::new(v.x * ang, v.y * ang, v.z * ang)
@@ -400,7 +400,7 @@ impl<N: BaseFloat + Clone> Rotation<Vec3<N>> for UnitQuat<N> {
     }
 }
 
-impl<N: Num + Clone> Rotate<Vec3<N>> for UnitQuat<N> {
+impl<N: BaseNum + Clone> Rotate<Vec3<N>> for UnitQuat<N> {
     #[inline]
     fn rotate(&self, v: &Vec3<N>) -> Vec3<N> {
         *self * *v
@@ -412,7 +412,7 @@ impl<N: Num + Clone> Rotate<Vec3<N>> for UnitQuat<N> {
     }
 }
 
-impl<N: Num + Clone> Rotate<Pnt3<N>> for UnitQuat<N> {
+impl<N: BaseNum + Clone> Rotate<Pnt3<N>> for UnitQuat<N> {
     #[inline]
     fn rotate(&self, p: &Pnt3<N>) -> Pnt3<N> {
         *self * *p
@@ -424,7 +424,7 @@ impl<N: Num + Clone> Rotate<Pnt3<N>> for UnitQuat<N> {
     }
 }
 
-impl<N: Num + Clone> Transform<Vec3<N>> for UnitQuat<N> {
+impl<N: BaseNum + Clone> Transform<Vec3<N>> for UnitQuat<N> {
     #[inline]
     fn transform(&self, v: &Vec3<N>) -> Vec3<N> {
         *self * *v
@@ -436,7 +436,7 @@ impl<N: Num + Clone> Transform<Vec3<N>> for UnitQuat<N> {
     }
 }
 
-impl<N: Num + Clone> Transform<Pnt3<N>> for UnitQuat<N> {
+impl<N: BaseNum + Clone> Transform<Pnt3<N>> for UnitQuat<N> {
     #[inline]
     fn transform(&self, p: &Pnt3<N>) -> Pnt3<N> {
         *self * *p
@@ -520,6 +520,7 @@ vec_sub_scalar_impl!(Quat, i16, QuatSubRhs, w, i, j, k)
 vec_sub_scalar_impl!(Quat, i8, QuatSubRhs, w, i, j, k)
 vec_sub_scalar_impl!(Quat, uint, QuatSubRhs, w, i, j, k)
 vec_sub_scalar_impl!(Quat, int, QuatSubRhs, w, i, j, k)
+zero_one_impl!(Quat, w, i, j, k)
 approx_eq_impl!(Quat, w, i, j, k)
 from_iterator_impl!(Quat, iterator, iterator, iterator, iterator)
 bounded_impl!(Quat, w, i, j, k)
diff --git a/src/structs/rot.rs b/src/structs/rot.rs
index d1e63a98..a5a69b48 100644
--- a/src/structs/rot.rs
+++ b/src/structs/rot.rs
@@ -2,11 +2,10 @@
 
 #![allow(missing_docs)]
 
-use std::num::{Zero, One, Num};
 use std::rand::{Rand, Rng};
 use traits::geometry::{Rotate, Rotation, AbsoluteRotate, RotationMatrix, Transform, ToHomogeneous,
                        Norm, Cross};
-use traits::structure::{Cast, Dim, Row, Col, BaseFloat};
+use traits::structure::{Cast, Dim, Row, Col, BaseFloat, BaseNum, Zero, One};
 use traits::operations::{Absolute, Inv, Transpose, ApproxEq};
 use structs::vec::{Vec1, Vec2, Vec3, Vec4, Vec2MulRhs, Vec3MulRhs, Vec4MulRhs};
 use structs::pnt::{Pnt2, Pnt3, Pnt4, Pnt2MulRhs, Pnt3MulRhs, Pnt4MulRhs};
@@ -104,13 +103,13 @@ impl<N: Clone + BaseFloat> Rot3<N> {
     ///   * `axisangle` - A vector representing the rotation. Its magnitude is the amount of rotation
     ///   in radian. Its direction is the axis of rotation.
     pub fn new(axisangle: Vec3<N>) -> Rot3<N> {
-        if Norm::sqnorm(&axisangle).is_zero() {
-            One::one()
+        if ::is_zero(&Norm::sqnorm(&axisangle)) {
+            ::one()
         }
         else {
             let mut axis   = axisangle;
             let angle      = axis.normalize();
-            let _1: N      = One::one();
+            let _1: N      = ::one();
             let ux         = axis.x.clone();
             let uy         = axis.y.clone();
             let uz         = axis.z.clone();
@@ -209,14 +208,14 @@ impl<N: Clone + BaseFloat + Cast<f64>>
 Rotation<Vec3<N>> for Rot3<N> {
     #[inline]
     fn rotation(&self) -> Vec3<N> {
-        let angle = ((self.submat.m11 + self.submat.m22 + self.submat.m33 - One::one()) / Cast::from(2.0)).acos();
+        let angle = ((self.submat.m11 + self.submat.m22 + self.submat.m33 - ::one()) / Cast::from(2.0)).acos();
 
         if angle != angle {
             // FIXME: handle that correctly
-            Zero::zero()
+            ::zero()
         }
-        else if angle.is_zero() {
-            Zero::zero()
+        else if ::is_zero(&angle) {
+            ::zero()
         }
         else {
             let m32_m23 = self.submat.m32 - self.submat.m23;
@@ -225,10 +224,10 @@ Rotation<Vec3<N>> for Rot3<N> {
 
             let denom = (m32_m23 * m32_m23 + m13_m31 * m13_m31 + m21_m12 * m21_m12).sqrt();
 
-            if denom.is_zero() {
+            if ::is_zero(&denom) {
                 // XXX: handle that properly
                 // panic!("Internal error: singularity.")
-                Zero::zero()
+                ::zero()
             }
             else {
                 let a_d = angle / denom;
diff --git a/src/structs/rot_macros.rs b/src/structs/rot_macros.rs
index ef1d06e4..82a105fd 100644
--- a/src/structs/rot_macros.rs
+++ b/src/structs/rot_macros.rs
@@ -34,7 +34,7 @@ macro_rules! rotate_impl(
             }
         }
 
-        impl<N: Num + Clone> $trhs<N> for $tv<N> {
+        impl<N: BaseNum + Clone> $trhs<N> for $tv<N> {
             #[inline]
             fn rotate(t: &$t<N>, v: &$tv<N>) -> $tv<N> {
                 *t * *v
@@ -46,7 +46,7 @@ macro_rules! rotate_impl(
             }
         }
 
-        impl<N: Num + Clone> $trhs<N> for $tp<N> {
+        impl<N: BaseNum + Clone> $trhs<N> for $tp<N> {
             #[inline]
             fn rotate(t: &$t<N>, p: &$tp<N>) -> $tp<N> {
                 *t * *p
@@ -83,7 +83,7 @@ macro_rules! transform_impl(
             }
         }
 
-        impl<N: Num + Clone> $trhs<N> for $tv<N> {
+        impl<N: BaseNum + Clone> $trhs<N> for $tv<N> {
             #[inline]
             fn transform(t: &$t<N>, v: &$tv<N>) -> $tv<N> {
                 t.rotate(v)
@@ -95,7 +95,7 @@ macro_rules! transform_impl(
             }
         }
 
-        impl<N: Num + Clone> $trhs<N> for $tp<N> {
+        impl<N: BaseNum + Clone> $trhs<N> for $tp<N> {
             #[inline]
             fn transform(t: &$t<N>, p: &$tp<N>) -> $tp<N> {
                 t.rotate(p)
@@ -122,7 +122,7 @@ macro_rules! dim_impl(
 
 macro_rules! rotation_matrix_impl(
     ($t: ident, $tlv: ident, $tav: ident) => (
-        impl<N: Zero + Num + Cast<f64> + BaseFloat> RotationMatrix<N, $tlv<N>, $tav<N>, $t<N>> for $t<N> {
+        impl<N: Zero + BaseNum + Cast<f64> + BaseFloat> RotationMatrix<N, $tlv<N>, $tav<N>, $t<N>> for $t<N> {
             #[inline]
             fn to_rot_mat(&self) -> $t<N> {
                 self.clone()
@@ -133,10 +133,10 @@ macro_rules! rotation_matrix_impl(
 
 macro_rules! one_impl(
     ($t: ident) => (
-        impl<N: Num + Clone> One for $t<N> {
+        impl<N: BaseNum + Clone> One for $t<N> {
             #[inline]
             fn one() -> $t<N> {
-                $t { submat: One::one() }
+                $t { submat: ::one() }
             }
         }
     )
@@ -144,7 +144,7 @@ macro_rules! one_impl(
 
 macro_rules! rot_mul_rot_impl(
     ($t: ident, $mulrhs: ident) => (
-        impl<N: Num + Clone> $mulrhs<N, $t<N>> for $t<N> {
+        impl<N: BaseNum + Clone> $mulrhs<N, $t<N>> for $t<N> {
             #[inline]
             fn binop(left: &$t<N>, right: &$t<N>) -> $t<N> {
                 $t { submat: left.submat * right.submat }
@@ -155,7 +155,7 @@ macro_rules! rot_mul_rot_impl(
 
 macro_rules! rot_mul_vec_impl(
     ($t: ident, $tv: ident, $mulrhs: ident) => (
-        impl<N: Num + Clone> $mulrhs<N, $tv<N>> for $tv<N> {
+        impl<N: BaseNum + Clone> $mulrhs<N, $tv<N>> for $tv<N> {
             #[inline]
             fn binop(left: &$t<N>, right: &$tv<N>) -> $tv<N> {
                 left.submat * *right
@@ -172,7 +172,7 @@ macro_rules! rot_mul_pnt_impl(
 
 macro_rules! vec_mul_rot_impl(
     ($t: ident, $tv: ident, $mulrhs: ident) => (
-        impl<N: Num + Clone> $mulrhs<N, $tv<N>> for $t<N> {
+        impl<N: BaseNum + Clone> $mulrhs<N, $tv<N>> for $t<N> {
             #[inline]
             fn binop(left: &$tv<N>, right: &$t<N>) -> $tv<N> {
                 *left * right.submat
@@ -281,7 +281,7 @@ macro_rules! index_impl(
 
 macro_rules! to_homogeneous_impl(
     ($t: ident, $tm: ident) => (
-        impl<N: Num + Clone> ToHomogeneous<$tm<N>> for $t<N> {
+        impl<N: BaseNum + Clone> ToHomogeneous<$tm<N>> for $t<N> {
             #[inline]
             fn to_homogeneous(m: &$t<N>) -> $tm<N> {
                 ToHomogeneous::to_homogeneous(&m.submat)
diff --git a/src/structs/spec/complex.rs b/src/structs/spec/complex.rs
index ec043e14..7a06d180 100644
--- a/src/structs/spec/complex.rs
+++ b/src/structs/spec/complex.rs
@@ -5,21 +5,21 @@ use extra::complex::Cmplx;
 use traits::operations::{Absolute, Inv};
 use traits::structure::{Dim};
 
-impl<N: Clone + Num> Absolute<Cmplx<N>> for Cmplx<N> {
+impl<N: Clone + BaseNum> Absolute<Cmplx<N>> for Cmplx<N> {
     #[inline]
     fn absolute(&self) -> Cmplx<N> {
         Cmplx::new(self.re.clone(), self.im.clone())
     }
 }
 
-impl<N: Clone + Num + NumCast + Zero> Inv for Cmplx<N> {
+impl<N: Clone + BaseNum + BaseNumCast + Zero> Inv for Cmplx<N> {
     #[inline]
     fn inverse(&self) -> Option<Cmplx<N>> {
         if self.is_zero() {
             None
         }
         else {
-            let _1: N   = NumCast::from(1.0);
+            let _1: N   = BaseNumCast::from(1.0);
             let divisor = _1 / (self.re * self.re - self.im * self.im);
 
             Some(Cmplx::new(self.re * divisor, -self.im * divisor))
@@ -32,7 +32,7 @@ impl<N: Clone + Num + NumCast + Zero> Inv for Cmplx<N> {
             false
         }
         else {
-            let _1: N   = NumCast::from(1.0);
+            let _1: N   = BaseNumCast::from(1.0);
             let divisor = _1 / (self.re * self.re - self.im * self.im);
 
             self.re = self.re  * divisor;
diff --git a/src/structs/spec/identity.rs b/src/structs/spec/identity.rs
index b33d2f25..6b2687f2 100644
--- a/src/structs/spec/identity.rs
+++ b/src/structs/spec/identity.rs
@@ -1,7 +1,8 @@
-use std::num::{One, Zero};
 use structs::mat;
 use traits::operations::{Inv, Transpose};
-use traits::geometry::{Translation, Translate, Rotation, Rotate, Transformation, Transform, AbsoluteRotate};
+use traits::structure::{Zero, One};
+use traits::geometry::{Translation, Translate, Rotation, Rotate, Transformation, Transform,
+                       AbsoluteRotate};
 
 impl One for mat::Identity {
     #[inline]
@@ -41,12 +42,12 @@ impl Transpose for mat::Identity {
 impl<V: Zero> Translation<V> for mat::Identity {
     #[inline]
     fn translation(&self) -> V {
-        Zero::zero()
+        ::zero()
     }
 
     #[inline]
     fn inv_translation(&self) -> V {
-        Zero::zero()
+        ::zero()
     }
 
     #[inline]
@@ -90,12 +91,12 @@ impl<V: Clone> Translate<V> for mat::Identity {
 impl<V: Zero> Rotation<V> for mat::Identity {
     #[inline]
     fn rotation(&self) -> V {
-        Zero::zero()
+        ::zero()
     }
 
     #[inline]
     fn inv_rotation(&self) -> V {
-        Zero::zero()
+        ::zero()
     }
 
     #[inline]
@@ -146,12 +147,12 @@ impl<V: Clone> AbsoluteRotate<V> for mat::Identity {
 impl<M: One> Transformation<M> for mat::Identity {
     #[inline]
     fn transformation(&self) -> M {
-        One::one()
+        ::one()
     }
 
     #[inline]
     fn inv_transformation(&self) -> M {
-        One::one()
+        ::one()
     }
 
     #[inline]
diff --git a/src/structs/spec/mat.rs b/src/structs/spec/mat.rs
index 767caf34..c41b6f44 100644
--- a/src/structs/spec/mat.rs
+++ b/src/structs/spec/mat.rs
@@ -1,12 +1,11 @@
-use std::num::{Zero, One, Num};
 use structs::vec::{Vec2, Vec3, Vec2MulRhs, Vec3MulRhs};
 use structs::pnt::{Pnt2, Pnt3, Pnt2MulRhs, Pnt3MulRhs};
 use structs::mat::{Mat1, Mat2, Mat3, Mat3MulRhs, Mat2MulRhs};
 use traits::operations::{Inv, Det, ApproxEq};
-use traits::structure::{Row, Col, BaseFloat};
+use traits::structure::{Row, Col, BaseNum};
 
 // some specializations:
-impl<N: Num + ApproxEq<N> + Clone> Inv for Mat1<N> {
+impl<N: BaseNum + ApproxEq<N> + Clone> Inv for Mat1<N> {
     #[inline]
     fn inv_cpy(m: &Mat1<N>) -> Option<Mat1<N>> {
         let mut res = m.clone();
@@ -21,11 +20,11 @@ impl<N: Num + ApproxEq<N> + Clone> Inv for Mat1<N> {
 
     #[inline]
     fn inv(&mut self) -> bool {
-        if ApproxEq::approx_eq(&self.m11, &Zero::zero()) {
+        if ApproxEq::approx_eq(&self.m11, &::zero()) {
             false
         }
         else {
-            let _1: N = One::one();
+            let _1: N = ::one();
 
             self.m11 = _1 / Det::det(self);
             true
@@ -33,7 +32,7 @@ impl<N: Num + ApproxEq<N> + Clone> Inv for Mat1<N> {
     }
 }
 
-impl<N: Num + ApproxEq<N> + Clone> Inv for Mat2<N> {
+impl<N: BaseNum + ApproxEq<N> + Clone> Inv for Mat2<N> {
     #[inline]
     fn inv_cpy(m: &Mat2<N>) -> Option<Mat2<N>> {
         let mut res = m.clone();
@@ -50,7 +49,7 @@ impl<N: Num + ApproxEq<N> + Clone> Inv for Mat2<N> {
     fn inv(&mut self) -> bool {
         let det = Det::det(self);
 
-        if ApproxEq::approx_eq(&det, &Zero::zero()) {
+        if ApproxEq::approx_eq(&det, &::zero()) {
             false
         }
         else {
@@ -63,7 +62,7 @@ impl<N: Num + ApproxEq<N> + Clone> Inv for Mat2<N> {
     }
 }
 
-impl<N: Num + ApproxEq<N> + Clone> Inv for Mat3<N> {
+impl<N: BaseNum + ApproxEq<N> + Clone> Inv for Mat3<N> {
     #[inline]
     fn inv_cpy(m: &Mat3<N>) -> Option<Mat3<N>> {
         let mut res = m.clone();
@@ -84,7 +83,7 @@ impl<N: Num + ApproxEq<N> + Clone> Inv for Mat3<N> {
 
         let det = self.m11 * minor_m12_m23 - self.m12 * minor_m11_m23 + self.m13 * minor_m11_m22;
 
-        if ApproxEq::approx_eq(&det, &Zero::zero()) {
+        if ApproxEq::approx_eq(&det, &::zero()) {
             false
         }
         else {
@@ -107,21 +106,21 @@ impl<N: Num + ApproxEq<N> + Clone> Inv for Mat3<N> {
     }
 }
 
-impl<N: Num + Clone> Det<N> for Mat1<N> {
+impl<N: BaseNum + Clone> Det<N> for Mat1<N> {
     #[inline]
     fn det(m: &Mat1<N>) -> N {
         m.m11.clone()
     }
 }
 
-impl<N: Num> Det<N> for Mat2<N> {
+impl<N: BaseNum> Det<N> for Mat2<N> {
     #[inline]
     fn det(m: &Mat2<N>) -> N {
         m.m11 * m.m22 - m.m21 * m.m12
     }
 }
 
-impl<N: Num> Det<N> for Mat3<N> {
+impl<N: BaseNum> Det<N> for Mat3<N> {
     #[inline]
     fn det(m: &Mat3<N>) -> N {
         let minor_m12_m23 = m.m22 * m.m33 - m.m32 * m.m23;
diff --git a/src/structs/spec/vec.rs b/src/structs/spec/vec.rs
index ebaf1b45..8f90b116 100644
--- a/src/structs/spec/vec.rs
+++ b/src/structs/spec/vec.rs
@@ -1,5 +1,4 @@
-use std::num::{Zero, One, Num};
-use traits::structure::{Cast, Row, Basis, BaseFloat};
+use traits::structure::{Cast, Row, Basis, BaseFloat, Zero, One};
 use traits::geometry::{Norm, Cross, CrossMatrix, UniformSphereSample};
 use structs::vec::{Vec1, Vec2, Vec3, Vec4};
 use structs::mat::Mat3;
@@ -34,9 +33,9 @@ impl<N: Neg<N> + Zero + Clone> CrossMatrix<Mat3<N>> for Vec3<N> {
     #[inline]
     fn cross_matrix(v: &Vec3<N>) -> Mat3<N> {
         Mat3::new(
-            Zero::zero(), -v.z        , v.y.clone(),
-            v.z.clone() , Zero::zero(), -v.x,
-            -v.y        , v.x.clone() , Zero::zero()
+            ::zero(), -v.z        , v.y.clone(),
+            v.z.clone() , ::zero(), -v.x,
+            -v.y        , v.x.clone() , ::zero()
         )
     }
 }
@@ -71,7 +70,7 @@ impl<N: Clone> Row<Vec1<N>> for Vec2<N> {
 impl<N: One> Basis for Vec1<N> {
     #[inline(always)]
     fn canonical_basis(f: |Vec1<N>| -> bool) {
-        f(Vec1::new(One::one()));
+        f(Vec1::new(::one()));
     }
 
     #[inline(always)]
@@ -80,7 +79,7 @@ impl<N: One> Basis for Vec1<N> {
     #[inline]
     fn canonical_basis_element(i: uint) -> Option<Vec1<N>> {
         if i == 0 {
-            Some(Vec1::new(One::one()))
+            Some(Vec1::new(::one()))
         }
         else {
             None
@@ -91,8 +90,8 @@ impl<N: One> Basis for Vec1<N> {
 impl<N: Clone + One + Zero + Neg<N>> Basis for Vec2<N> {
     #[inline(always)]
     fn canonical_basis(f: |Vec2<N>| -> bool) {
-        if !f(Vec2::new(One::one(), Zero::zero())) { return };
-        f(Vec2::new(Zero::zero(), One::one()));
+        if !f(Vec2::new(::one(), ::zero())) { return };
+        f(Vec2::new(::zero(), ::one()));
     }
 
     #[inline]
@@ -103,10 +102,10 @@ impl<N: Clone + One + Zero + Neg<N>> Basis for Vec2<N> {
     #[inline]
     fn canonical_basis_element(i: uint) -> Option<Vec2<N>> {
         if i == 0 {
-            Some(Vec2::new(One::one(), Zero::zero()))
+            Some(Vec2::new(::one(), ::zero()))
         }
         else if i == 1 {
-            Some(Vec2::new(Zero::zero(), One::one()))
+            Some(Vec2::new(::zero(), ::one()))
         }
         else {
             None
@@ -117,19 +116,19 @@ impl<N: Clone + One + Zero + Neg<N>> Basis for Vec2<N> {
 impl<N: BaseFloat> Basis for Vec3<N> {
     #[inline(always)]
     fn canonical_basis(f: |Vec3<N>| -> bool) {
-        if !f(Vec3::new(One::one(), Zero::zero(), Zero::zero())) { return };
-        if !f(Vec3::new(Zero::zero(), One::one(), Zero::zero())) { return };
-        f(Vec3::new(Zero::zero(), Zero::zero(), One::one()));
+        if !f(Vec3::new(::one(), ::zero(), ::zero())) { return };
+        if !f(Vec3::new(::zero(), ::one(), ::zero())) { return };
+        f(Vec3::new(::zero(), ::zero(), ::one()));
     }
 
     #[inline(always)]
     fn orthonormal_subspace_basis(n: &Vec3<N>, f: |Vec3<N>| -> bool) {
         let a = 
             if n.x.clone().abs() > n.y.clone().abs() {
-                Norm::normalize_cpy(&Vec3::new(n.z.clone(), Zero::zero(), -n.x))
+                Norm::normalize_cpy(&Vec3::new(n.z.clone(), ::zero(), -n.x))
             }
             else {
-                Norm::normalize_cpy(&Vec3::new(Zero::zero(), -n.z, n.y.clone()))
+                Norm::normalize_cpy(&Vec3::new(::zero(), -n.z, n.y.clone()))
             };
 
         if !f(Cross::cross(&a, n)) { return };
@@ -139,13 +138,13 @@ impl<N: BaseFloat> Basis for Vec3<N> {
     #[inline]
     fn canonical_basis_element(i: uint) -> Option<Vec3<N>> {
         if i == 0 {
-            Some(Vec3::new(One::one(), Zero::zero(), Zero::zero()))
+            Some(Vec3::new(::one(), ::zero(), ::zero()))
         }
         else if i == 1 {
-            Some(Vec3::new(Zero::zero(), One::one(), Zero::zero()))
+            Some(Vec3::new(::zero(), ::one(), ::zero()))
         }
         else if i == 2 {
-            Some(Vec3::new(Zero::zero(), Zero::zero(), One::one()))
+            Some(Vec3::new(::zero(), ::zero(), ::one()))
         }
         else {
             None
@@ -227,7 +226,7 @@ static SAMPLES_3_F64: [Vec3<f64>, ..42] = [
 impl<N: One + Clone> UniformSphereSample for Vec1<N> {
     #[inline(always)]
     fn sample(f: |Vec1<N>| -> ()) {
-        f(One::one())
+        f(::one())
      }
 }
 
diff --git a/src/structs/spec/vec0.rs b/src/structs/spec/vec0.rs
index ed575ceb..6b51fd46 100644
--- a/src/structs/spec/vec0.rs
+++ b/src/structs/spec/vec0.rs
@@ -1,12 +1,24 @@
 use std::mem;
-use std::num::{Zero, One, Bounded, Num};
 use std::slice::{Items, MutItems};
 use std::iter::{Iterator, FromIterator};
 use traits::operations::ApproxEq;
-use traits::structure::{Iterable, IterableMut, Indexable, Basis, Dim, Shape, BaseFloat};
+use traits::structure::{Iterable, IterableMut, Indexable, Basis, Dim, Shape, BaseFloat, BaseNum,
+                        Zero, One, Bounded};
 use traits::geometry::{Translation, Dot, Norm};
 use structs::vec;
 
+impl<N> Zero for vec::Vec0<N> {
+    #[inline]
+    fn zero() -> vec::Vec0<N> {
+        vec::Vec0
+    }
+
+    #[inline]
+    fn is_zero(&self) -> bool {
+        true
+    }
+}
+
 impl<N> Index<uint, N> for vec::Vec0<N> {
     #[inline]
     fn index(&self, _: &uint) -> &N {
@@ -107,10 +119,10 @@ impl<N: Neg<N>> Neg<vec::Vec0<N>> for vec::Vec0<N> {
     }
 }
 
-impl<N: Num> Dot<N> for vec::Vec0<N> {
+impl<N: BaseNum> Dot<N> for vec::Vec0<N> {
     #[inline]
     fn dot(_: &vec::Vec0<N>, _: &vec::Vec0<N>) -> N {
-        Zero::zero()
+        ::zero()
     }
 }
 
@@ -167,22 +179,22 @@ impl<N: Clone + Add<N, N> + Neg<N>> Translation<vec::Vec0<N>> for vec::Vec0<N> {
 impl<N: BaseFloat> Norm<N> for vec::Vec0<N> {
     #[inline]
     fn sqnorm(_: &vec::Vec0<N>) -> N {
-        Zero::zero()
+        ::zero()
     }
 
     #[inline]
     fn norm(_: &vec::Vec0<N>) -> N {
-        Zero::zero()
+        ::zero()
     }
 
     #[inline]
     fn normalize_cpy(_: &vec::Vec0<N>) -> vec::Vec0<N> {
-        Zero::zero()
+        ::zero()
     }
 
     #[inline]
     fn normalize(&mut self) -> N {
-        Zero::zero()
+        ::zero()
     }
 }
 
diff --git a/src/structs/vec.rs b/src/structs/vec.rs
index f7d7d0e6..0cae3b8b 100644
--- a/src/structs/vec.rs
+++ b/src/structs/vec.rs
@@ -3,7 +3,6 @@
 #![allow(missing_docs)] // we allow missing to avoid having to document the dispatch traits.
 
 use std::mem;
-use std::num::{Zero, One, Bounded, Num};
 use std::slice::{Items, MutItems};
 use std::iter::{Iterator, FromIterator};
 use traits::operations::{ApproxEq, POrd, POrdering, PartialLess, PartialEqual,
@@ -12,7 +11,7 @@ use traits::operations::{ApproxEq, POrd, POrdering, PartialLess, PartialEqual,
 use traits::geometry::{Transform, Rotate, FromHomogeneous, ToHomogeneous, Dot, Norm,
                        Translation, Translate};
 use traits::structure::{Basis, Cast, Dim, Indexable, Iterable, IterableMut, VecAsPnt, Shape,
-                        NumVec, FloatVec, BaseFloat};
+                        NumVec, FloatVec, BaseFloat, BaseNum, Zero, One, Bounded};
 use structs::pnt::{Pnt1, Pnt2, Pnt3, Pnt4, Pnt5, Pnt6};
 
 
@@ -121,7 +120,7 @@ vec_sub_scalar_impl!(Vec1, int, Vec1SubRhs, x)
 translation_impl!(Vec1)
 norm_impl!(Vec1, x)
 approx_eq_impl!(Vec1, x)
-one_impl!(Vec1, x)
+zero_one_impl!(Vec1, x)
 from_iterator_impl!(Vec1, iterator)
 bounded_impl!(Vec1, x)
 axpy_impl!(Vec1, x)
@@ -226,7 +225,7 @@ vec_sub_scalar_impl!(Vec2, int, Vec2SubRhs, x, y)
 translation_impl!(Vec2)
 norm_impl!(Vec2, x, y)
 approx_eq_impl!(Vec2, x, y)
-one_impl!(Vec2, x, y)
+zero_one_impl!(Vec2, x, y)
 from_iterator_impl!(Vec2, iterator, iterator)
 bounded_impl!(Vec2, x, y)
 axpy_impl!(Vec2, x, y)
@@ -336,7 +335,7 @@ vec_sub_scalar_impl!(Vec3, int, Vec3SubRhs, x, y, z)
 translation_impl!(Vec3)
 norm_impl!(Vec3, x, y ,z)
 approx_eq_impl!(Vec3, x, y, z)
-one_impl!(Vec3, x, y, z)
+zero_one_impl!(Vec3, x, y, z)
 from_iterator_impl!(Vec3, iterator, iterator, iterator)
 bounded_impl!(Vec3, x, y, z)
 axpy_impl!(Vec3, x, y, z)
@@ -446,7 +445,7 @@ vec_sub_scalar_impl!(Vec4, int, Vec4SubRhs, x, y, z, w)
 translation_impl!(Vec4)
 norm_impl!(Vec4, x, y, z, w)
 approx_eq_impl!(Vec4, x, y, z, w)
-one_impl!(Vec4, x, y, z, w)
+zero_one_impl!(Vec4, x, y, z, w)
 from_iterator_impl!(Vec4, iterator, iterator, iterator, iterator)
 bounded_impl!(Vec4, x, y, z, w)
 axpy_impl!(Vec4, x, y, z, w)
@@ -557,7 +556,7 @@ vec_sub_scalar_impl!(Vec5, int, Vec5SubRhs, x, y, z, w, a)
 translation_impl!(Vec5)
 norm_impl!(Vec5, x, y, z, w, a)
 approx_eq_impl!(Vec5, x, y, z, w, a)
-one_impl!(Vec5, x, y, z, w, a)
+zero_one_impl!(Vec5, x, y, z, w, a)
 from_iterator_impl!(Vec5, iterator, iterator, iterator, iterator, iterator)
 bounded_impl!(Vec5, x, y, z, w, a)
 axpy_impl!(Vec5, x, y, z, w, a)
@@ -670,7 +669,7 @@ vec_sub_scalar_impl!(Vec6, int, Vec6SubRhs, x, y, z, w, a, b)
 translation_impl!(Vec6)
 norm_impl!(Vec6, x, y, z, w, a, b)
 approx_eq_impl!(Vec6, x, y, z, w, a, b)
-one_impl!(Vec6, x, y, z, w, a, b)
+zero_one_impl!(Vec6, x, y, z, w, a, b)
 from_iterator_impl!(Vec6, iterator, iterator, iterator, iterator, iterator, iterator)
 bounded_impl!(Vec6, x, y, z, w, a, b)
 axpy_impl!(Vec6, x, y, z, w, a, b)
diff --git a/src/structs/vec_macros.rs b/src/structs/vec_macros.rs
index b8e502c2..7a4a771b 100644
--- a/src/structs/vec_macros.rs
+++ b/src/structs/vec_macros.rs
@@ -135,9 +135,9 @@ macro_rules! vec_axis_impl(
             /// Create a unit vector with its `$comp0` component equal to 1.0.
             #[inline]
             pub fn $comp0() -> $t<N> {
-                let mut res: $t<N> = Zero::zero();
+                let mut res: $t<N> = ::zero();
 
-                res.$comp0 = One::one();
+                res.$comp0 = ::one();
 
                 res
             }
@@ -146,9 +146,9 @@ macro_rules! vec_axis_impl(
                 /// Create a unit vector with its `$compN` component equal to 1.0.
                 #[inline]
                 pub fn $compN() -> $t<N> {
-                    let mut res: $t<N> = Zero::zero();
+                    let mut res: $t<N> = ::zero();
 
-                    res.$compN = One::one();
+                    res.$compN = ::one();
 
                     res
                 }
@@ -308,10 +308,10 @@ macro_rules! basis_impl(
                 let mut basis: Vec<$t<N>> = Vec::new();
 
                 for i in range(0u, $dim) {
-                    let mut basis_element : $t<N> = Zero::zero();
+                    let mut basis_element : $t<N> = ::zero();
 
                     unsafe {
-                        basis_element.set_fast(i, One::one());
+                        basis_element.set_fast(i, ::one());
                     }
 
                     if basis.len() == $dim - 1 {
@@ -326,7 +326,7 @@ macro_rules! basis_impl(
                         elt = elt - *v * Dot::dot(&elt, v)
                     };
 
-                    if !ApproxEq::approx_eq(&Norm::sqnorm(&elt), &Zero::zero()) {
+                    if !ApproxEq::approx_eq(&Norm::sqnorm(&elt), &::zero()) {
                         let new_element = Norm::normalize_cpy(&elt);
 
                         if !f(new_element.clone()) { return };
@@ -339,10 +339,10 @@ macro_rules! basis_impl(
             #[inline]
             fn canonical_basis_element(i: uint) -> Option<$t<N>> {
                 if i < $dim {
-                    let mut basis_element : $t<N> = Zero::zero();
+                    let mut basis_element : $t<N> = ::zero();
 
                     unsafe {
-                        basis_element.set_fast(i, One::one());
+                        basis_element.set_fast(i, ::one());
                     }
 
                     Some(basis_element)
@@ -424,7 +424,7 @@ macro_rules! neg_impl(
 
 macro_rules! dot_impl(
     ($t: ident, $comp0: ident $(,$compN: ident)*) => (
-        impl<N: Num> Dot<N> for $t<N> {
+        impl<N: BaseNum> Dot<N> for $t<N> {
             #[inline]
             fn dot(a: &$t<N>, b: &$t<N>) -> N {
                 a.$comp0 * b.$comp0 $(+ a.$compN * b.$compN )*
@@ -608,17 +608,33 @@ macro_rules! approx_eq_impl(
     )
 )
 
-macro_rules! one_impl(
+macro_rules! zero_one_impl(
     ($t: ident, $comp0: ident $(,$compN: ident)*) => (
         impl<N: One> One for $t<N> {
             #[inline]
             fn one() -> $t<N> {
                 $t {
-                    $comp0: One::one()
-                    $(, $compN: One::one() )*
+                    $comp0: ::one()
+                    $(, $compN: ::one() )*
                 }
             }
         }
+
+        impl<N: Zero> Zero for $t<N> {
+            #[inline]
+            fn zero() -> $t<N> {
+                $t {
+                    $comp0: ::zero()
+                    $(, $compN: ::zero() )*
+                }
+            }
+
+            #[inline]
+            fn is_zero(&self) -> bool {
+                self.$comp0.is_zero()
+                $(&& self.$compN.is_zero() )*
+            }
+        }
     )
 )
 
@@ -659,7 +675,7 @@ macro_rules! vec_to_homogeneous_impl(
     ($t: ident, $t2: ident, $extra: ident, $comp0: ident $(,$compN: ident)*) => (
         impl<N: Clone + One + Zero> ToHomogeneous<$t2<N>> for $t<N> {
             fn to_homogeneous(v: &$t<N>) -> $t2<N> {
-                let mut res: $t2<N> = Zero::zero();
+                let mut res: $t2<N> = ::zero();
 
                 res.$comp0    = v.$comp0.clone();
                 $( res.$compN = v.$compN.clone(); )*
@@ -674,7 +690,7 @@ macro_rules! vec_from_homogeneous_impl(
     ($t: ident, $t2: ident, $extra: ident, $comp0: ident $(,$compN: ident)*) => (
         impl<N: Clone + Div<N, N> + One + Zero> FromHomogeneous<$t2<N>> for $t<N> {
             fn from(v: &$t2<N>) -> $t<N> {
-                let mut res: $t<N> = Zero::zero();
+                let mut res: $t<N> = ::zero();
 
                 res.$comp0    = v.$comp0.clone();
                 $( res.$compN = v.$compN.clone(); )*
@@ -765,11 +781,11 @@ macro_rules! vec_as_pnt_impl(
 macro_rules! num_float_vec_impl(
     ($t: ident $(,$trhs: ident)*) => (
         impl<N> NumVec<N> for $t<N>
-            where N: Num $(+ $trhs<N, $t<N>>)* {
+            where N: BaseNum + Zero $(+ $trhs<N, $t<N>>)* {
         }
 
         impl<N> FloatVec<N> for $t<N>
-            where N: Num + Zero + One + ApproxEq<N> + BaseFloat $(+ $trhs<N, $t<N>>)* {
+            where N: BaseNum + Zero + One + ApproxEq<N> + BaseFloat $(+ $trhs<N, $t<N>>)* {
         }
     )
 )
diff --git a/src/traits/mod.rs b/src/traits/mod.rs
index 64a90352..7a54df3e 100644
--- a/src/traits/mod.rs
+++ b/src/traits/mod.rs
@@ -6,7 +6,8 @@ pub use traits::geometry::{AbsoluteRotate, Cross, CrossMatrix, Dot, FromHomogene
 
 pub use traits::structure::{FloatVec, FloatPnt, Basis, Cast, Col, Dim, Indexable, Iterable,
                             IterableMut, Mat, SquareMat, Row, NumVec, NumPnt, PntAsVec, VecAsPnt,
-                            ColSlice, RowSlice, Diag, Eye, Shape, BaseFloat};
+                            ColSlice, RowSlice, Diag, Eye, Shape, BaseFloat, BaseNum, Zero, One,
+                            Bounded};
 
 pub use traits::operations::{Absolute, ApproxEq, Axpy, Cov, Det, Inv, LMul, Mean, Outer, POrd,
                              RMul, ScalarAdd, ScalarSub, ScalarMul, ScalarDiv, Transpose, EigenQR};
diff --git a/src/traits/operations.rs b/src/traits/operations.rs
index 7333eff4..b47e6baa 100644
--- a/src/traits/operations.rs
+++ b/src/traits/operations.rs
@@ -257,27 +257,6 @@ pub trait EigenQR<N, V>: SquareMat<N, V> {
     fn eigen_qr(m: &Self, eps: &N, niter: uint) -> (Self, V);
 }
 
-
-// /// Cholesky decomposition.
-// pub trait Chol {
-//     /// Performs the cholesky decomposition on `self`. The resulting upper-triangular matrix is
-//     /// returned. Returns `None` if the matrix is not symetric positive-definite.
-//     fn chol(self) -> Option<Self>;
-// 
-//     /// Performs the cholesky decomposition on `self`. The resulting upper-triangular matrix is
-//     /// written to a given parameter. If the decomposition fails `false` is returned; the state of
-//     /// the output parameter is undefined.
-//     fn chol_to(&self, out: &mut Self) -> bool {
-//         match self.chol() {
-//             None => false,
-//             Some(decomp) => {
-//                 *out = decomp;
-//                 true
-//             }
-//         }
-//     }
-// }
-
 // XXX: those two traits should not exist since there is generalized operator overloading of Add
 // and Sub.
 // However, using the same trait multiple time as a trait bound (ex: impl<T: Add<N, V> + Add<V, V>)
@@ -347,7 +326,11 @@ pub trait Axpy<N> {
 }
 
 /*
- * Some implementation for scalar types.
+ *
+ *
+ * Some implementations for scalar types.
+ *
+ *
  */
 // FIXME: move this to another module ?
 macro_rules! impl_absolute(
@@ -373,6 +356,7 @@ macro_rules! impl_absolute_id(
 
 impl_absolute!(f32)
 impl_absolute!(f64)
+impl_absolute!(i8)
 impl_absolute!(i16)
 impl_absolute!(i32)
 impl_absolute!(i64)
diff --git a/src/traits/structure.rs b/src/traits/structure.rs
index e6dbbbfa..029d496f 100644
--- a/src/traits/structure.rs
+++ b/src/traits/structure.rs
@@ -1,13 +1,21 @@
 //! Traits giving structural informations on linear algebra objects or the space they live in.
 
-use std::num::{Zero, One, FloatMath, Num};
+use std::num::{Int, Float, FloatMath};
 use std::slice::{Items, MutItems};
 use traits::operations::{RMul, LMul, Axpy, Transpose, Inv, Absolute};
 use traits::geometry::{Dot, Norm, Orig};
 
-pub trait BaseFloat: FloatMath + Zero + One + Num + Absolute<Self> {
+/// Basic integral numeric trait.
+pub trait BaseNum: Zero + One + Add<Self, Self> + Sub<Self, Self> + Mul<Self, Self> +
+                   Div<Self, Self> + Rem<Self, Self> + Neg<Self> + PartialEq + Absolute<Self> {
 }
 
+/// Basic floating-point number numeric trait.
+pub trait BaseFloat: FloatMath + BaseNum {
+}
+
+impl BaseNum for f32 { }
+impl BaseNum for f64 { }
 impl BaseFloat for f32 { }
 impl BaseFloat for f64 { }
 
@@ -41,8 +49,29 @@ pub trait Eye {
     fn new_identity(dim: uint) -> Self;
 }
 
-// XXX: we keep ScalarAdd and ScalarSub here to avoid trait impl conflict (overriding) between the
-// different Add/Sub traits. This is _so_ unfortunate…
+/// Additive identity.
+pub trait Zero {
+    /// Returns the additive identity.
+    fn zero() -> Self;
+    /// Tests if `self` is exactly zero.
+    fn is_zero(&self) -> bool;
+}
+
+/// Multiplicative identity.
+pub trait One {
+    /// Returns the multiplicative identity.
+    fn one() -> Self;
+}
+
+/// Types that have maximum and minimum value.
+pub trait Bounded {
+    /// The minimum value.
+    #[inline]
+    fn min_value() -> Self;
+    /// The maximum value.
+    #[inline]
+    fn max_value() -> Self;
+}
 
 // FIXME: return an iterator instead
 /// Traits of objects which can form a basis (typically vectors).
@@ -223,3 +252,74 @@ pub trait FloatPnt<N: BaseFloat, V: Norm<N>>: NumPnt<N, V> {
         Norm::norm(&(*a - *b))
     }
 }
+
+/*
+ *
+ *
+ * Some implementations for builtin types.
+ *
+ *
+ */
+macro_rules! impl_zero_one(
+    ($n: ty, $zero: expr, $one: expr) => {
+        impl Zero for $n {
+            #[inline]
+            fn zero() -> $n {
+                $zero
+            }
+
+            #[inline]
+            fn is_zero(&self) -> bool {
+                *self == $zero
+            }
+        }
+
+        impl One for $n {
+            fn one() -> $n {
+                $one
+            }
+        }
+    }
+)
+
+impl_zero_one!(f32, 0.0, 1.0)
+impl_zero_one!(f64, 0.0, 1.0)
+impl_zero_one!(i8, 0, 1)
+impl_zero_one!(i16, 0, 1)
+impl_zero_one!(i32, 0, 1)
+impl_zero_one!(i64, 0, 1)
+impl_zero_one!(int, 0, 1)
+impl_zero_one!(u8, 0, 1)
+impl_zero_one!(u16, 0, 1)
+impl_zero_one!(u32, 0, 1)
+impl_zero_one!(u64, 0, 1)
+impl_zero_one!(uint, 0, 1)
+
+macro_rules! impl_bounded(
+    ($n: ty, $min: expr, $max: expr) => {
+        impl Bounded for $n {
+            #[inline]
+            fn min_value() -> $n {
+                $min
+            }
+
+            #[inline]
+            fn max_value() -> $n {
+                $max
+            }
+        }
+    }
+)
+
+impl_bounded!(f32, Float::min_value(), Float::max_value())
+impl_bounded!(f64, Float::min_value(), Float::max_value())
+impl_bounded!(i8, Int::min_value(), Int::max_value())
+impl_bounded!(i16, Int::min_value(), Int::max_value())
+impl_bounded!(i32, Int::min_value(), Int::max_value())
+impl_bounded!(i64, Int::min_value(), Int::max_value())
+impl_bounded!(int, Int::min_value(), Int::max_value())
+impl_bounded!(u8, Int::min_value(), Int::max_value())
+impl_bounded!(u16, Int::min_value(), Int::max_value())
+impl_bounded!(u32, Int::min_value(), Int::max_value())
+impl_bounded!(u64, Int::min_value(), Int::max_value())
+impl_bounded!(uint, Int::min_value(), Int::max_value())