proposition: Lemma leif_refl x C : reflect (x <= x ?= iff C) C.
proof: Proof. by apply: (iffP idP) => [-> | <-] //; split; rewrite ?eqxx. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)