proposition: Lemma eq_fneg f g : f =1 g -> fneg f =1 fneg g.
proof: Proof. by move=> eq_fg x; rewrite /fneg eq_fg. Qed.
imports: mathcomp(all_ssreflect all_algebra) mathcomp.classical(boolp) xfinmap ereal reals discrete realseq mathcomp.classical(classical_sets functions mathcomp_extra) topology