1 (**************************************************************************)
4 (* ||A|| A project by Andrea Asperti *)
6 (* ||I|| Developers: *)
7 (* ||T|| The HELM team. *)
8 (* ||A|| http://helm.cs.unibo.it *)
10 (* \ / This file is distributed under the terms of the *)
11 (* v GNU General Public License Version 2 *)
13 (**************************************************************************)
15 include "basics/logic.ma".
16 include "ground/notation/xoa/false_0.ma".
17 include "ground/notation/xoa/true_0.ma".
18 include "ground/notation/xoa/or_2.ma".
19 include "ground/notation/xoa/and_2.ma".
29 (* LOGIC ********************************************************************)
31 (* Constructions with land **************************************************)
33 lemma commutative_and (A) (B):
35 #A #B * /2 width=1 by conj/