X-Git-Url: http://matita.cs.unibo.it/gitweb/?p=helm.git;a=blobdiff_plain;f=matita%2Fmatita%2Fcontribs%2Flambdadelta%2Fapps_2%2Fmodels%2Fmodel_props.ma;h=073d5db6278a04b2b831af10fbe4d0c9f22ddf57;hp=863e3d063f60121290266416ee6167600dadcd32;hb=e880d6eab5e1700f4a625ddcd7d0fa8f0cce2dcc;hpb=f86ab1580e0bab7f8cada3cc7ffdf80f40e3de9a

diff --git a/matita/matita/contribs/lambdadelta/apps_2/models/model_props.ma b/matita/matita/contribs/lambdadelta/apps_2/models/model_props.ma
index 863e3d063..073d5db62 100644
--- a/matita/matita/contribs/lambdadelta/apps_2/models/model_props.ma
+++ b/matita/matita/contribs/lambdadelta/apps_2/models/model_props.ma
@@ -45,3 +45,23 @@ lemma seq_sym (M): is_model M → symmetric … (sq M).
 
 lemma seq_trans (M): is_model M → Transitive … (sq M).
 /3 width=5 by mr, mq/ qed-.
+
+lemma seq_canc_sn (M): is_model M → left_cancellable … (sq M).
+/3 width=3 by seq_trans, seq_sym/ qed-.
+
+lemma seq_canc_dx (M): is_model M → right_cancellable … (sq M).
+/3 width=3 by seq_trans, seq_sym/ qed-.
+
+lemma ti_lref_vlift_eq (M): is_model M →
+                            ∀gv,lv,d,i. ⟦#i⟧[gv,⫯[i←d]lv] ≗{M} d.
+#M #HM #gv #lv #d #i
+@(seq_trans … HM) [2: @ml // | skip ]
+>vlift_eq /2 width=1 by mq/
+qed.
+
+lemma ti_lref_vlift_gt (M): is_model M →
+                            ∀gv,lv,d,i. ⟦#(↑i)⟧[gv,⫯[d]lv] ≗{M} ⟦#i⟧[gv,lv].
+#M #HM #gv #lv #d #i
+@(mr … HM) [4,5: @(seq_sym … HM) @(ml … HM) |1,2: skip ]
+>vlift_gt /2 width=1 by mq/
+qed.