diff --git a/headers/vmath.hpp/vmath_fun.hpp b/headers/vmath.hpp/vmath_fun.hpp
index 7e8ba90..c753df6 100644
--- a/headers/vmath.hpp/vmath_fun.hpp
+++ b/headers/vmath.hpp/vmath_fun.hpp
@@ -229,13 +229,13 @@ namespace vmath_hpp
     template < typename T >
     [[nodiscard]] std::enable_if_t<std::is_arithmetic_v<T>, T>
     constexpr min(T x, T y) noexcept {
-        return std::min(x, y);
+        return x < y ? x : y;
     }
 
     template < typename T >
     [[nodiscard]] std::enable_if_t<std::is_arithmetic_v<T>, T>
     constexpr max(T x, T y) noexcept {
-        return std::max(x, y);
+        return x < y ? y : x;
     }
 
     template < typename T >
@@ -287,8 +287,6 @@ namespace vmath_hpp
         return std::isfinite(x);
     }
 
-    //
-
     template < typename T >
     [[nodiscard]] std::enable_if_t<std::is_floating_point_v<T>, T>
     fma(T x, T y, T z) noexcept {
diff --git a/headers/vmath.hpp/vmath_fwd.hpp b/headers/vmath.hpp/vmath_fwd.hpp
index 01f8ea6..81a8bbc 100644
--- a/headers/vmath.hpp/vmath_fwd.hpp
+++ b/headers/vmath.hpp/vmath_fwd.hpp
@@ -9,8 +9,6 @@
 #include <cmath>
 #include <cstddef>
 
-#include <algorithm>
-#include <functional>
 #include <stdexcept>
 #include <type_traits>
 #include <utility>
diff --git a/headers/vmath.hpp/vmath_mat_fun.hpp b/headers/vmath.hpp/vmath_mat_fun.hpp
index 273295d..1fedbb1 100644
--- a/headers/vmath.hpp/vmath_mat_fun.hpp
+++ b/headers/vmath.hpp/vmath_mat_fun.hpp
@@ -103,7 +103,7 @@ namespace vmath_hpp
 
     template < typename T, std::size_t Size >
     [[nodiscard]] constexpr mat<T, Size> operator-(const mat<T, Size>& xs) {
-        return map(std::negate<>(), xs);
+        return map([](const vec<T, Size>& x){ return -x; }, xs);
     }
 
     // operator+
@@ -120,7 +120,7 @@ namespace vmath_hpp
 
     template < typename T, std::size_t Size >
     [[nodiscard]] constexpr mat<T, Size> operator+(const mat<T, Size>& xs, const mat<T, Size>& ys) {
-        return zip(std::plus<>(), xs, ys);
+        return zip([](const vec<T, Size>& x, const vec<T, Size>& y){ return x + y; }, xs, ys);
     }
 
     // operator+=
@@ -149,7 +149,7 @@ namespace vmath_hpp
 
     template < typename T, std::size_t Size >
     [[nodiscard]] constexpr mat<T, Size> operator-(const mat<T, Size>& xs, const mat<T, Size>& ys) {
-        return zip(std::minus<>(), xs, ys);
+        return zip([](const vec<T, Size>& x, const vec<T, Size>& y){ return x - y; }, xs, ys);
     }
 
     // operator-=
@@ -281,7 +281,7 @@ namespace vmath_hpp
 
     template < typename T, std::size_t Size >
     [[nodiscard]] constexpr mat<T, Size> operator/(const mat<T, Size>& xs, const mat<T, Size>& ys) {
-        return zip(std::divides<>(), xs, ys);
+        return zip([](const vec<T, Size>& x, const vec<T, Size>& y){ return x / y; }, xs, ys);
     }
 
     // operator/=
diff --git a/headers/vmath.hpp/vmath_vec_fun.hpp b/headers/vmath.hpp/vmath_vec_fun.hpp
index 4227849..a4a3fbd 100644
--- a/headers/vmath.hpp/vmath_vec_fun.hpp
+++ b/headers/vmath.hpp/vmath_vec_fun.hpp
@@ -100,7 +100,7 @@ namespace vmath_hpp
 
     template < typename T, std::size_t Size >
     [[nodiscard]] constexpr vec<T, Size> operator-(const vec<T, Size>& xs) {
-        return map(std::negate<>(), xs);
+        return map([](T x){ return -x; }, xs);
     }
 
     // operator+
@@ -117,7 +117,7 @@ namespace vmath_hpp
 
     template < typename T, std::size_t Size >
     [[nodiscard]] constexpr vec<T, Size> operator+(const vec<T, Size>& xs, const vec<T, Size>& ys) {
-        return zip(std::plus<>(), xs, ys);
+        return zip([](T x, T y){ return x + y; }, xs, ys);
     }
 
     // operator+=
@@ -146,7 +146,7 @@ namespace vmath_hpp
 
     template < typename T, std::size_t Size >
     [[nodiscard]] constexpr vec<T, Size> operator-(const vec<T, Size>& xs, const vec<T, Size>& ys) {
-        return zip(std::minus<>(), xs, ys);
+        return zip([](T x, T y){ return x - y; }, xs, ys);
     }
 
     // operator-=
@@ -175,7 +175,7 @@ namespace vmath_hpp
 
     template < typename T, std::size_t Size >
     [[nodiscard]] constexpr vec<T, Size> operator*(const vec<T, Size>& xs, const vec<T, Size>& ys) {
-        return zip(std::multiplies<>(), xs, ys);
+        return zip([](T x, T y){ return x * y; }, xs, ys);
     }
 
     // operator*=
@@ -204,7 +204,7 @@ namespace vmath_hpp
 
     template < typename T, std::size_t Size >
     [[nodiscard]] constexpr vec<T, Size> operator/(const vec<T, Size>& xs, const vec<T, Size>& ys) {
-        return zip(std::divides<>(), xs, ys);
+        return zip([](T x, T y){ return x / y; }, xs, ys);
     }
 
     // operator/=
diff --git a/untests/vmath_mat_fun_tests.cpp b/untests/vmath_mat_fun_tests.cpp
index 705f76f..d67d99b 100644
--- a/untests/vmath_mat_fun_tests.cpp
+++ b/untests/vmath_mat_fun_tests.cpp
@@ -191,14 +191,14 @@ TEST_CASE("vmath/mat_fun") {
         STATIC_REQUIRE(inverse(float4x4(0.5)) == float4x4(2.f));
 
         {
-            constexpr float4x4 m1 = translate(float3{1.f,2.f,3.f});
+            constexpr float4x4 m1 = translate(float3(1.f, 2.f, 3.f));
             constexpr float4x4 inv_m1 = inverse(m1);
-            constexpr float4x4 ref_m1 = translate(float3{-1.f,-2.f,-3.f});
+            constexpr float4x4 ref_m1 = translate(float3(-1.f, -2.f, -3.f));
             STATIC_REQUIRE(inv_m1 == approx4x4(ref_m1));
         }
 
         {
-            const float3 axis = normalize(float3{1.f,2.f,3.f});
+            const float3 axis = normalize(float3(1.f, 2.f, 3.f));
             const float4x4 m1 = rotate(0.5f,axis);
             const float4x4 inv_m1 = inverse(m1);
             const float4x4 ref_m1 = rotate(-0.5f,axis);
@@ -206,7 +206,7 @@ TEST_CASE("vmath/mat_fun") {
         }
 
         {
-            const float3 axis = normalize(float3{1.f,2.f,3.f});
+            const float3 axis = normalize(float3(1.f, 2.f, 3.f));
             const float3x3 m1 = float3x3(rotate(0.5f,axis));
             const float3x3 inv_m1 = inverse(m1);
             const float3x3 ref_m1 = float3x3(rotate(-0.5f,axis));
@@ -214,7 +214,7 @@ TEST_CASE("vmath/mat_fun") {
         }
 
         {
-            const float3 axis = normalize(float3{0.f,0.f,3.f});
+            const float3 axis = normalize(float3(0.f, 0.f, 3.f));
             const float2x2 m1 = float2x2(rotate(0.5f,axis));
             const float2x2 inv_m1 = inverse(m1);
             const float2x2 ref_m1 = float2x2(rotate(-0.5f,axis));
diff --git a/untests/vmath_tests.hpp b/untests/vmath_tests.hpp
index ac1f22f..d76de7c 100644
--- a/untests/vmath_tests.hpp
+++ b/untests/vmath_tests.hpp
@@ -10,7 +10,7 @@
 #include <vmath.hpp/vmath_mat.hpp>
 #include <vmath.hpp/vmath_mat_fun.hpp>
 
-#include <limits>
+#include <cfloat>
 
 #define STATIC_REQUIRE(...)\
     static_assert(__VA_ARGS__, #__VA_ARGS__);\
@@ -25,7 +25,29 @@ namespace vmath_tests
     using namespace vmath_hpp;
 
     template < typename T >
-    inline constexpr T epsilon = std::numeric_limits<T>::epsilon() * 100;
+    struct approx_epsilon;
+
+    template <>
+    struct approx_epsilon<int> {
+        static constexpr int value = 0;
+    };
+
+    template <>
+    struct approx_epsilon<float> {
+        static constexpr float value = FLT_EPSILON * 100;
+    };
+
+    template <>
+    struct approx_epsilon<double> {
+        static constexpr float value = DBL_EPSILON * 100;
+    };
+
+    template < typename T >
+    inline constexpr T approx_epsilon_v = approx_epsilon<T>::value;
+
+    //
+    //
+    //
 
     template < typename T >
     struct approx {
@@ -103,22 +125,22 @@ namespace vmath_tests
 
     template < typename T >
     constexpr bool operator==(const T& l, const approx<T>& r) {
-        return equal_to(l, r.value, epsilon<T>);
+        return equal_to(l, r.value, approx_epsilon_v<T>);
     }
 
     template < typename T >
     constexpr bool operator==(const vec<T, 2>& l, const approx2<T>& r) {
-        return all(equal_to(l, r.value, epsilon<T>));
+        return all(equal_to(l, r.value, approx_epsilon_v<T>));
     }
 
     template < typename T >
     constexpr bool operator==(const vec<T, 3>& l, const approx3<T>& r) {
-        return all(equal_to(l, r.value, epsilon<T>));
+        return all(equal_to(l, r.value, approx_epsilon_v<T>));
     }
 
     template < typename T >
     constexpr bool operator==(const vec<T, 4>& l, const approx4<T>& r) {
-        return all(equal_to(l, r.value, epsilon<T>));
+        return all(equal_to(l, r.value, approx_epsilon_v<T>));
     }
 
     template < typename T >