<mp-units/framework/representation_concepts.h>
template<
typename T,
auto V>
concept RepresentationOf = ((QuantitySpec<MP_UNITS_REMOVE_CONST(decltype(V))> &&
((detail::QuantityKindSpec<MP_UNITS_REMOVE_CONST(decltype(V))> && detail::SomeRepresentation<T>) ||
detail::IsOfCharacter<T, V.character>)) ||
(std::same_as<quantity_character, decltype(V)> && detail::IsOfCharacter<T, V>));