+++ /dev/null
-(**************************************************************************)
-(* ___ *)
-(* ||M|| *)
-(* ||A|| A project by Andrea Asperti *)
-(* ||T|| *)
-(* ||I|| Developers: *)
-(* ||T|| The HELM team. *)
-(* ||A|| http://helm.cs.unibo.it *)
-(* \ / *)
-(* \ / This file is distributed under the terms of the *)
-(* v GNU General Public License Version 2 *)
-(* *)
-(**************************************************************************)
-
-include "basics/relations.ma".
-
-(* ADDITIONAL PROPERTIES OF RELATIONS ***************************************)
-
-lemma replace2: ∀A,B:Type[0]. ∀R:relation2 A B. ∀x1,y1,x2,y2.
- R x1 x2 → y1 = x1 → y2 = x2 → R y1 y2.
-// qed-.