std::indirectly_comparable(3)

NAME
std::indirectly_comparable - std::indirectly_comparable

Synopsis
   Defined in header <iterator>
   template< class I1, class I2, class Comp,
             class Proj1 = std::identity, class Proj2 = std::identity >
   concept indirectly_comparable = (since C++20)
       std::indirect_binary_predicate<Comp, std::projected<I1, Proj1>,
   std::projected<I2, Proj2>>;
   The concept indirectly_comparable specifies the fundamental algorithm requirement
   for comparing values across two independent ranges.
   Semantic requirements
   indirectly_comparable is modeled only if all concepts it subsumes are modeled.

See also
                        specifies that a callable type, when invoked with the
   indirect_binary_predicate result of dereferencing two indirectly_readable types,
   (C++20) satisfies predicate
                        (concept)