proposition: Lemma lem_iso : forall x1 y1 x2 y2 theta : Rdefinitions.R, Rgeom.dist_euc x1 y1 x2 y2 = Rgeom.dist_euc (Rgeom.xr x1 y1 theta) (Rgeom.yr x1 y1 theta) (Rgeom.xr x2 y2 theta) (Rgeom.yr x2 y2 theta).
proof: Proof. hammer. Restart. scongruence use: Rgeom.isometric_rotation. Qed.
imports: Hammer(Hammer) Arith