diff --git a/include/loki/details/pddl/equal_to.hpp b/include/loki/details/pddl/equal_to.hpp
index fd82788..cafd9c0 100644
--- a/include/loki/details/pddl/equal_to.hpp
+++ b/include/loki/details/pddl/equal_to.hpp
@@ -19,7 +19,6 @@
 #define LOKI_INCLUDE_LOKI_PDDL_EQUAL_TO_HPP_
 
 #include "loki/details/pddl/declarations.hpp"
-#include "loki/details/utils/concepts.hpp"
 
 #include <functional>
 #include <variant>
diff --git a/include/loki/details/pddl/hash.hpp b/include/loki/details/pddl/hash.hpp
index a73a76a..08343ef 100644
--- a/include/loki/details/pddl/hash.hpp
+++ b/include/loki/details/pddl/hash.hpp
@@ -19,8 +19,6 @@
 #define LOKI_INCLUDE_LOKI_PDDL_HASH_HPP_
 
 #include "loki/details/pddl/declarations.hpp"
-#include "loki/details/utils/concepts.hpp"
-#include "loki/details/utils/unique_factory.hpp"
 
 #include <cstddef>
 #include <cstdint>
@@ -79,11 +77,10 @@ struct UniquePDDLHasher<ForwardRange>
 };
 
 /// Spezialization for std::variant.
-template<typename Variant>
-requires IsVariant<Variant>
-struct UniquePDDLHasher<Variant>
+template<typename... Ts>
+struct UniquePDDLHasher<std::variant<Ts...>>
 {
-    size_t operator()(const Variant& variant) const
+    size_t operator()(const std::variant<Ts...>& variant) const
     {
         return std::visit([](const auto& arg) { return UniquePDDLHasher<decltype(arg)>()(arg); }, variant);
     }
diff --git a/include/loki/details/utils/concepts.hpp b/include/loki/details/utils/concepts.hpp
deleted file mode 100644
index 7c7320a..0000000
--- a/include/loki/details/utils/concepts.hpp
+++ /dev/null
@@ -1,79 +0,0 @@
-/*
- * Copyright (C) 2023 Dominik Drexler and Simon Stahlberg
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *<
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <https://www.gnu.org/licenses/>.
- */
-
-#ifndef LOKI_INCLUDE_LOKI_UTILS_CONCEPTS_HPP_
-#define LOKI_INCLUDE_LOKI_UTILS_CONCEPTS_HPP_
-
-#include <concepts>
-#include <cstddef>
-#include <memory>
-#include <ranges>
-#include <type_traits>
-#include <variant>
-
-namespace loki
-{
-
-template<typename T>
-struct dependent_false : std::false_type
-{
-};
-
-template<typename T>
-concept IsArithmetic = std::is_arithmetic_v<T>;
-
-template<typename T>
-concept IsIntegral = std::is_integral_v<T>;
-
-template<typename T>
-concept IsUnsignedIntegral = std::is_integral_v<T> && std::is_unsigned_v<T>;
-
-template<typename T, typename Value>
-concept IsRangeOver = std::ranges::range<T> && std::same_as<std::ranges::range_value_t<T>, Value>;
-
-template<typename T>
-struct is_variant : std::false_type
-{
-};
-
-template<typename... Types>
-struct is_variant<std::variant<Types...>> : std::true_type
-{
-};
-
-template<typename T>
-concept IsVariant = is_variant<T>::value;
-
-static_assert(IsVariant<std::variant<int, float>>);
-static_assert(!IsVariant<int>);
-
-template<typename T>
-concept IsDereferencable = requires(T a)
-{
-    // Check that the type supports dereferencing
-    { *a };
-    // Check that the type can be converted to bool
-    { static_cast<bool>(a) };
-};
-
-static_assert(IsDereferencable<std::shared_ptr<int>>);
-static_assert(IsDereferencable<int*>);
-static_assert(!IsDereferencable<int>);
-
-}
-
-#endif