proposition: Lemma subc_ge0 x y : lec 0 (y - x) = lec x y.
proof: Proof. by move: x y => [a b] [c d] /=; simpc; rewrite subr_ge0 subr_eq0. Qed.
imports: HB(structures) mathcomp.ssreflect.ssreflect mathcomp(ssrfun ssrbool eqtype ssrnat seq choice fintype) mathcomp(bigop order ssralg ssrint div ssrnum rat poly closed_field) mathcomp(polyrcf matrix mxalgebra tuple mxpoly zmodp binomial realalg) mathcomp(mxpoly)