std::Relation

Defined in header <concepts>
template <class R, class T, class U>
concept Relation =
  std::Predicate<R, T, T> && std::Predicate<R, U, U> &&
  std::Predicate<R, T, U> && std::Predicate<R, U, T>;
(1) (since C++20)

The concept Relation<R, T, U> specifies that R defines a binary relation over the set of expressions whose type and value category are those encoded by either T or U.

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