proposition: Lemma leR_min z : z <= min x y <-> z <= x /\ z <= y.
proof: Proof. split=> [lezm | [lezx lezy]]; first by split; apply: leR_trans lezm _. by case: (min x y) / IFR_cases => _ [] [_ ->]. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div order) mathcomp(ssralg ssrnum ssrint rat intdiv) Coq(Morphisms Setoid) fourcolor(real realsyntax)