X-Git-Url: http://matita.cs.unibo.it/gitweb/?p=helm.git;a=blobdiff_plain;f=matita%2Fmatita%2Fcontribs%2Flambdadelta%2Fground%2Flib%2Fsubset_ext.ma;h=5839bfb108d754e7cd2cd4f7d2fdba00a0d1aac6;hp=5d623ad16f3afa6e60c2080b71f9a5bf6b6d3c27;hb=8f1a123e61ff079b1f9ad63cc915470ec7e6abf3;hpb=df1bcd1387439133c0c33f597a5f8b2331c07772

diff --git a/matita/matita/contribs/lambdadelta/ground/lib/subset_ext.ma b/matita/matita/contribs/lambdadelta/ground/lib/subset_ext.ma
index 5d623ad16..5839bfb10 100644
--- a/matita/matita/contribs/lambdadelta/ground/lib/subset_ext.ma
+++ b/matita/matita/contribs/lambdadelta/ground/lib/subset_ext.ma
@@ -19,6 +19,11 @@ include "ground/lib/subset.ma".
 definition subset_ext_f1 (A1) (A0) (f:A1→A0): 𝒫❨A1❩ → 𝒫❨A0❩ ≝
            λu1,a0. ∃∃a1. a1 ϵ u1 & f a1 = a0.
 
+definition subset_ext_f1_1 (A11) (A21) (A0) (f1:A11→A0) (f2:A21→A0): 𝒫❨A11❩ → 𝒫❨A21❩ → 𝒫❨A0❩ ≝
+           λu11,u21,a0.
+           ∨∨ subset_ext_f1 A11 A0 f1 u11 a0
+            | subset_ext_f1 A21 A0 f2 u21 a0.
+
 definition subset_ext_p1 (A1) (Q:predicate A1): predicate (𝒫❨A1❩) ≝
            λu1. ∀a1. a1 ϵ u1 → Q a1.
 
@@ -28,6 +33,14 @@ lemma subset_in_ext_f1_dx (A1) (A0) (f) (u1) (a1):
       a1 ϵ u1 → f a1 ϵ subset_ext_f1 A1 A0 f u1.
 /2 width=3 by ex2_intro/ qed.
 
+lemma subset_in_ext_f1_1_dx_1 (A11) (A21) (A0) (f1) (f2) (u11) (u21) (a11):
+      a11 ϵ u11 → f1 a11 ϵ subset_ext_f1_1 A11 A21 A0 f1 f2 u11 u21.
+/3 width=3 by subset_in_ext_f1_dx, or_introl/ qed.
+
+lemma subset_in_ext_f1_1_dx_2 (A11) (A21) (A0) (f1) (f2) (u11) (u21) (a21):
+      a21 ϵ u21 → f2 a21 ϵ subset_ext_f1_1 A11 A21 A0 f1 f2 u11 u21.
+/3 width=3 by subset_in_ext_f1_dx, or_intror/ qed.
+
 (* Basic inversions *********************************************************)
 
 lemma subset_in_inv_ext_p1_dx (A1) (Q) (u1) (a1):