proposition: Fact meetss s : meet s s = s.
proof: Proof. by elim: s => [|? ? ih] //=; rewrite meetxx ih. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)