diff --git a/include/etl/functional.h b/include/etl/functional.h
index 73b1685b..3c1c55b4 100644
--- a/include/etl/functional.h
+++ b/include/etl/functional.h
@@ -303,7 +303,7 @@ namespace etl
     typedef int is_transparent;
 
     template <typename T1, typename T2>
-    constexpr auto operator()(T1&& lhs, T2&& rhs) const -> decltype(static_cast<T1&&>(lhs) < static_cast<T2&&>(rhs))
+    constexpr auto operator()(T1&& lhs, T2&& rhs) const -> decltype(static_cast<T1&&>(lhs) == static_cast<T2&&>(rhs))
     {
       return static_cast<T1&&>(lhs) == static_cast<T2&&>(rhs);
     }
@@ -329,7 +329,7 @@ namespace etl
     typedef int is_transparent;
 
     template <typename T1, typename T2>
-    constexpr auto operator()(T1&& lhs, T2&& rhs) const -> decltype(static_cast<T1&&>(lhs) < static_cast<T2&&>(rhs))
+    constexpr auto operator()(T1&& lhs, T2&& rhs) const -> decltype(!(static_cast<T1&&>(lhs) == static_cast<T2&&>(rhs)))
     {
       return !(static_cast<T1&&>(lhs) == static_cast<T2&&>(rhs));
     }