dedekind::category::detail_comprehension::KeptByTheWalk Concept Reference

The walk's own order already is Order's under Rank: the chain descends by prior, so its elements fall along it, and a monotone rank under descending, or an antitone one under ascending, keeps them in order. order_by is then the identity. More...

Concept definition

template<typename Rank, typename Order>
concept dedekind::category::detail_comprehension::KeptByTheWalk = 
    (IsMonotone<Rank> && std::same_as<Order, descending>) ||
    (IsAntiMonotone<Rank> && std::same_as<Order, ascending>)

Detailed Description

The walk's own order already is Order's under Rank: the chain descends by prior, so its elements fall along it, and a monotone rank under descending, or an antitone one under ascending, keeps them in order. order_by is then the identity.