proposition: Lemma swapN (p : Plane) : swap (- p) = - swap p.
proof: Proof. by rewrite -mulN1r swapZ scaleN1r. Qed.
imports: axiomsKnuth mathcomp(all_ssreflect ssralg matrix ssrnum vector reals) mathcomp(normedtype order) mathcomp.algebra_tactics(ring) mathcomp.zify(zify)