X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fmatita%2Flib%2Fturing%2Funiversal%2Fmove_char_c.ma;h=f970da13eebcd535a0e7fa72ea29cd41d87d5744;hb=0a8212f3e87b75e8ab47dc853e612a9a3e1d2544;hp=685f32782e0a567f1b8d218a925c853bd1377e47;hpb=81926a297143f39c5de262a678e60f5aaf0bb13a;p=helm.git

diff --git a/matita/matita/lib/turing/universal/move_char_c.ma b/matita/matita/lib/turing/universal/move_char_c.ma
index 685f32782..f970da13e 100644
--- a/matita/matita/lib/turing/universal/move_char_c.ma
+++ b/matita/matita/lib/turing/universal/move_char_c.ma
@@ -107,24 +107,13 @@ definition Rmcc_step_false ≝
     left ? t1 ≠ [] →  current alpha t1 ≠ None alpha → 
       current alpha t1 = Some alpha sep ∧ t2 = t1.
     
-lemma loop_S_true : 
-  ∀A,n,f,p,a.  p a = true → 
-  loop A (S n) f p a = Some ? a. /2/
-qed.
-
-lemma loop_S_false : 
-  ∀A,n,f,p,a.  p a = false → 
-  loop A (S n) f p a = loop A n f p (f a).
-normalize #A #n #f #p #a #Hpa >Hpa %
-qed.
-
-lemma trans_init_sep: 
+lemma mcc_trans_init_sep: 
   ∀alpha,sep,x.
   trans ? (mcc_step alpha sep) 〈〈0,x〉,Some ? sep〉 = 〈〈4,sep〉,None ?〉.
 #alpha #sep #x normalize >(\b ?) //
 qed.
  
-lemma trans_init_not_sep: 
+lemma mcc_trans_init_not_sep: 
   ∀alpha,sep,x,y.y == sep = false → 
   trans ? (mcc_step alpha sep) 〈〈0,x〉,Some ? y〉 = 〈〈1,y〉,Some ? 〈y,L〉〉.
 #alpha #sep #x #y #H1 normalize >H1 //
@@ -149,8 +138,8 @@ lemma sem_mcc_step :
     @(ex_intro ?? (mk_config ?? 〈4,sep〉 (midtape ? lt c rt)))
     % [ % 
         [ >(\P Hc) >loop_S_false // >loop_S_true 
-         [ @eq_f whd in ⊢ (??%?); >trans_init_sep %
-         |>(\P Hc) whd in ⊢(??(???(???%))?); >trans_init_sep % ]
+         [ @eq_f whd in ⊢ (??%?); >mcc_trans_init_sep %
+         |>(\P Hc) whd in ⊢(??(???(???%))?); >mcc_trans_init_sep % ]
         |   #Hfalse destruct ]
       |#_ #H1 #H2 % // normalize >(\P Hc) % ]
   | @(ex_intro ?? 4) cases lt
@@ -185,7 +174,7 @@ definition R_move_char_c ≝
      b ≠ sep → memb ? sep rs1 = false → 
      t2 = midtape alpha (a::reverse ? rs1@b::ls) sep rs2).
     
-lemma sem_while_move_char :
+lemma sem_move_char_c :
   ∀alpha,sep.
   WRealize alpha (move_char_c alpha sep) (R_move_char_c alpha sep).
 #alpha #sep #inc #i #outc #Hloop
@@ -228,4 +217,30 @@ lapply (sem_while … (sem_mcc_step alpha sep) inc i outc Hloop) [%]
       >reverse_cons >associative_append @IH //
     ]
   ]
+qed.
+
+lemma terminate_move_char_c :
+  ∀alpha,sep.∀t,b,a,ls,rs. t = midtape alpha (a::ls) b rs →  
+  (b = sep ∨ memb ? sep rs = true) → Terminate alpha (move_char_c alpha sep) t.
+#alpha #sep #t #b #a #ls #rs #Ht #Hsep
+@(terminate_while … (sem_mcc_step alpha sep))
+  [%
+  |generalize in match Hsep; -Hsep
+   generalize in match Ht; -Ht
+   generalize in match ls; -ls
+   generalize in match a; -a
+   generalize in match b; -b
+   generalize in match t; -t
+   elim rs 
+    [#t #b #a #ls #Ht #Hsep % #tinit 
+     whd in ⊢ (%→?); #H @False_ind
+     cases (H … Ht) #Hb #_ cases Hb #eqb @eqb 
+     cases Hsep // whd in ⊢ ((??%?)→?); #abs destruct
+    |#r0 #rs0 #Hind #t #b #a #ls #Ht #Hsep % #tinit
+     whd in ⊢ (%→?); #H 
+     cases (H … Ht) #Hbsep #Htinit
+     @(Hind … Htinit) cases Hsep 
+      [#Hb @False_ind /2/ | #Hmemb cases (orb_true_l … Hmemb)
+        [#eqsep %1 >(\P eqsep) // | #H %2 //]
+  ]
 qed.
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