proposition: Lemma neq_creal_sym x y : x != y -> y != x.
proof: Proof. move=> neq_xy; pose_big_enough i. apply: (@neq_crealP (lbound neq_xy) i i); by rewrite ?lbound_gt0 1?distrC ?(lbound_of neq_xy). by close. Qed.
imports: mathcomp.ssreflect.ssreflect mathcomp(ssrfun ssrbool eqtype ssrnat seq choice fintype) mathcomp(bigop order ssralg ssrnum ssrint rat poly polydiv polyorder) mathcomp(perm matrix mxpoly polyXY binomial bigenough)