X-Git-Url: http://matita.cs.unibo.it/gitweb/?p=helm.git;a=blobdiff_plain;f=matita%2Fmatita%2Fcontribs%2Flambdadelta%2Fground%2Farith%2Fnat_minus_plus.ma;h=bb8c911bc91b92b14eade2599003dda8ced21d7b;hp=3e018b7759cfa8b16bb6ce6c0ac779941bdf3539;hb=19b0a814861157ba05f23877d5cd94059f52c2e8;hpb=21de0d35017656c5a55528390b54b0b2ae395b44

diff --git a/matita/matita/contribs/lambdadelta/ground/arith/nat_minus_plus.ma b/matita/matita/contribs/lambdadelta/ground/arith/nat_minus_plus.ma
index 3e018b775..bb8c911bc 100644
--- a/matita/matita/contribs/lambdadelta/ground/arith/nat_minus_plus.ma
+++ b/matita/matita/contribs/lambdadelta/ground/arith/nat_minus_plus.ma
@@ -25,6 +25,7 @@ lemma nminus_plus_sn_refl_sn (m) (n): m = m + n - n.
 #n #IH <nplus_succ_dx <nminus_succ_bi //
 qed.
 
+(*** minus_plus_m_m *)
 lemma nminus_plus_sn_refl_dx (m) (n): m = n + m - n.
 #m #n <nplus_comm //
 qed.
@@ -37,13 +38,9 @@ qed-.
 
 (*** minus_plus_plus_l *)
 lemma nminus_plus_dx_bi (m) (n) (o): m - n = (m + o) - (n + o).
-#m #n #o <nminus_plus_assoc <nminus_minus_comm //
+#m #n #o <nminus_plus_assoc <nminus_comm //
 qed.
 
-(*** plus_minus_plus_plus_l *) (**)
-lemma plus_minus_plus_plus_l: ∀z,x,y,h. z + (x + h) - (y + h) = z + x - y.
-// qed-.
-
 (* Helper constructions with nplus ******************************************)
 
 (*** plus_to_minus *)
@@ -62,7 +59,7 @@ lemma eq_inv_plus_nminus_refl_sn (m) (n) (o):
       m + o = m - n →
       ∨∨ ∧∧ 𝟎 = m & 𝟎 = o
        | ∧∧ 𝟎 = n & 𝟎 = o.
-#m #n @(nat_ind_succ_2 … m n) -m -n
+#m #n @(nat_ind_2_succ … m n) -m -n
 [ /3 width=1 by or_introl, conj/
 | #m #o #Ho
   lapply (eq_inv_nplus_bi_sn … (𝟎) Ho) -Ho
@@ -70,7 +67,7 @@ lemma eq_inv_plus_nminus_refl_sn (m) (n) (o):
 | #m #n #IH #o
   <nminus_succ_bi >nplus_succ_shift #Ho
   elim (IH … Ho) -IH -Ho * #_ #H
-  elim (eq_inv_nzero_succ … H)
+  elim (eq_inv_zero_nsucc … H)
 ]
 qed-.