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 "ground/lib/subset_inclusion.ma".
16 include "ground/lib/subset_ext.ma".
18 (* EXTENSIONS FOR SUBSETS ***************************************************)
20 (* Constructions with subset_inclusion **************************************)
22 lemma subset_inclusion_ext_f1_bi (A1) (A0) (f) (u1) (v1):
23 u1 ⊆ v1 → subset_ext_f1 A1 A0 f u1 ⊆ subset_ext_f1 A1 A0 f v1.
24 #A1 #A0 #f #u1 #v1 #Huv1 #a0 * #a1 #Hau1 #H destruct
25 /3 width=3 by subset_in_ext_f1_dx/
28 lemma subset_inclusion_ext_p1_trans (A1) (Q) (u1) (v1):
29 u1 ⊆ v1 → subset_ext_p1 A1 Q v1 → subset_ext_p1 A1 Q u1.
30 #A1 #Q #u1 #v1 #Huv1 #Hv1