X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fmatita%2Flibrary%2Fdidactic%2Fexercises%2Fnatural_deduction1.ma;h=c2778fbc5c0b548296f75fd5e0642810558d411e;hb=026c6c5b0e094b2e6e8244909bc5ac3d88b70b9c;hp=8f90dd67c20305403c0dda77b0e63f20b1d9ba2e;hpb=ece1166d5202b74ee25bdceef1b4951de979a99b;p=helm.git

diff --git a/helm/software/matita/library/didactic/exercises/natural_deduction1.ma b/helm/software/matita/library/didactic/exercises/natural_deduction1.ma
index 8f90dd67c..c2778fbc5 100644
--- a/helm/software/matita/library/didactic/exercises/natural_deduction1.ma
+++ b/helm/software/matita/library/didactic/exercises/natural_deduction1.ma
@@ -54,7 +54,7 @@ apply rule (⇒_i [h1] ((G ∧ L ⇒ E) ⇒ F ∧ L ⇒ E));
 apply rule (⇒_i [h2] (F ∧ L ⇒ E));
 apply rule (⇒_i [h3] (E));
 apply rule (∨_e (G∨¬G) [h4] (E) [h4] (E));
-	[ apply rule (lem EM);
+	[ apply rule (lem 0 EM);
 	| apply rule (⇒_e (G∧L⇒E) (G∧L));
 	    [ apply rule (discharge [h2]);
 	    | apply rule (∧_i (G) (L));
@@ -123,7 +123,7 @@ apply rule (⇒_i [h2] ((¬G ⇒ ¬H) ⇒ H ⇒ E));
 apply rule (⇒_i [h3] (H ⇒ E));
 apply rule (⇒_i [h4] (E));
 apply rule (∨_e (G∨¬G) [h5] (E) [h5] (E));
-	[apply rule (lem EM);
+	[apply rule (lem 0 EM);
 	| apply rule (∨_e (E∨F) [h6] (E) [h6] (E));
 	   [ apply rule (⇒_e (H ⇒ E∨F) (H));
 	       [ apply rule (discharge [h2]);