def eq_flip
import bend-kit-collections@0.1.4.1/PROOF.bend as PROOFimport Base
import bend-kit-collections@0.1.4.1/LAWS.bend as Laws
967def eq_flip(
968 ~K: Data, ~cmp: K -> K -> Cmp, ~flip: Flip(~K, ~cmp), +x: K, +y: K,
969 e: {cmp(x, y) == EQ{} : Cmp}
970) -> {cmp(y, x) == EQ{} : Cmp}:
971 Equal.trans(Cmp, cmp(y, x), Laws.flip(cmp(x, y)), EQ{}, flip(x, y),
972 Equal.cong(Cmp, Cmp, c => Laws.flip(c), cmp(x, y), EQ{}, e))