< cpp‎ | experimental‎ | ranges
Technical specifications
Filesystem library (filesystem TS)
Library fundamentals (library fundamentals TS)
Library fundamentals 2 (library fundamentals 2 TS)
Extensions for parallelism (parallelism TS)
Extensions for parallelism 2 (parallelism TS v2)
Extensions for concurrency (concurrency TS)
Concepts (concepts TS)
Ranges (ranges TS)
Special mathematical functions (special math TR)
Concepts library
Core language concepts
Object concepts
Comparison concepts
Callable concepts

URNG concept
template < class R, class T, class U >
concept bool StrictWeakOrder = ranges::Relation<R, T, U>;
(1) (ranges TS)

The concept StrictWeakOrder<R, T, U> specifies that the Relation R imposes a strict weak ordering on its arguments. A relation r is a strict weak ordering if

  • it is irreflexive: for all x, r(x, x) is false;
  • it is transitive: for all a, b and c, if r(a, b) and r(b, c) are both true then r(a, c) is true;
  • let e(a, b) be !r(a, b) && !r(b, a), then e is transitive: e(a, b) && e(b, c) implies e(a, c).

Under these conditions, it can be shown that e is an equivalence relation, and r induces a strict total ordering on the equivalence classes determined by e.

[edit] Notes

The distinction between Relation and StrictWeakOrder is purely semantic.