From 0a21dcbee5c00208edf949bf511d2d1768833a32 Mon Sep 17 00:00:00 2001
From: Andrea Asperti <andrea.asperti@unibo.it>
Date: Tue, 15 Oct 2013 08:21:09 +0000
Subject: [PATCH] renaming files

---
 .../lib/turing/multi_to_mono/shift_trace.ma   | 397 ++++++++++++++++++
 ...t_trace_machines.ma => shift_trace_aux.ma} |   0
 2 files changed, 397 insertions(+)
 create mode 100644 matita/matita/lib/turing/multi_to_mono/shift_trace.ma
 rename matita/matita/lib/turing/multi_to_mono/{shift_trace_machines.ma => shift_trace_aux.ma} (100%)

diff --git a/matita/matita/lib/turing/multi_to_mono/shift_trace.ma b/matita/matita/lib/turing/multi_to_mono/shift_trace.ma
new file mode 100644
index 000000000..9ff88de28
--- /dev/null
+++ b/matita/matita/lib/turing/multi_to_mono/shift_trace.ma
@@ -0,0 +1,397 @@
+include "turing/auxiliary_machines1.ma".
+include "turing/multi_to_mono/shift_trace_aux.ma".
+
+(******************************************************************************)
+(* mtiL: complete move L for tape i. We reaching the left border of trace i,  *)
+(* add a blank if there is no more tape, then move the i-trace and finally    *)
+(* come back to the head position.                                            *)
+(******************************************************************************)
+
+(* we say that a tape is regular if for any trace after the first blank we
+  only have other blanks *)
+  
+definition all_blanks_in ≝ λsig,l.
+  ∀x. mem ? x l → x = blank sig.  
+ 
+definition regular_i  ≝ λsig,n.λl:list (multi_sig sig n).λi.
+  all_blanks_in ? (after_blank ? (trace sig n i l)).
+
+definition regular_trace ≝ λsig,n,a.λls,rs:list (multi_sig sig n).λi.
+  Or (And (regular_i sig n (a::ls) i) (regular_i sig n rs i))
+     (And (regular_i sig n ls i) (regular_i sig n (a::rs) i)).
+         
+axiom regular_tail: ∀sig,n,l,i.
+  regular_i sig n l i → regular_i sig n (tail ? l) i.
+  
+axiom regular_extend: ∀sig,n,l,i.
+   regular_i sig n l i → regular_i sig n (l@[all_blank sig n]) i.
+
+axiom all_blank_after_blank: ∀sig,n,l1,b,l2,i. 
+  nth i ? (vec … b) (blank ?) = blank ? → 
+  regular_i sig n (l1@b::l2) i → all_blanks_in ? (trace sig n i l2).
+   
+lemma regular_trace_extl:  ∀sig,n,a,ls,rs,i.
+  regular_trace sig n a ls rs i → 
+    regular_trace sig n a (ls@[all_blank sig n]) rs i.
+#sig #n #a #ls #rs #i *
+  [* #H1 #H2 % % // @(regular_extend … H1)
+  |* #H1 #H2 %2 % // @(regular_extend … H1)
+  ]
+qed.
+
+lemma regular_cons_hd_rs: ∀sig,n.∀a:multi_sig sig n.∀ls,rs1,rs2,i.
+  regular_trace sig n a ls (rs1@rs2) i → 
+    regular_trace sig n a ls (rs1@((hd ? rs2 (all_blank …))::(tail ? rs2))) i.
+#sig #n #a #ls #rs1 #rs2 #i cases rs2 [2: #b #tl #H @H] 
+*[* #H1 >append_nil #H2 %1 % 
+   [@H1 | whd in match (hd ???); @(regular_extend … rs1) //]
+ |* #H1 >append_nil #H2 %2 % 
+   [@H1 | whd in match (hd ???); @(regular_extend … (a::rs1)) //]
+ ]
+qed.
+
+lemma eq_trace_to_regular : ∀sig,n.∀a1,a2:multi_sig sig n.∀ls1,ls2,rs1,rs2,i.
+   nth i ? (vec … a1) (blank ?) = nth i ? (vec … a2) (blank ?) →
+   trace sig n i ls1 = trace sig n i ls2 → 
+   trace sig n i rs1 = trace sig n i rs2 →
+   regular_trace sig n a1 ls1 rs1 i → 
+     regular_trace sig n a2 ls2 rs2 i.
+#sig #n #a1 #a2 #ls1 #ls2 #rs1 #rs2 #i #H1 #H2 #H3 #H4
+whd in match (regular_trace ??????); whd in match (regular_i ????);
+whd in match (regular_i ?? rs2 ?); whd in match (regular_i ?? ls2 ?);
+whd in match (regular_i ?? (a2::rs2) ?); whd in match (trace ????);
+<trace_def whd in match (trace ??? (a2::rs2)); <trace_def 
+<H1 <H2 <H3 @H4
+qed.
+
+(******************************* move_to_blank_L ******************************)
+(* we compose machines together to reduce the number of output cases, and 
+   improve semantics *)
+   
+definition move_to_blank_L ≝ λsig,n,i.
+  (move_until ? L (no_blank sig n i)) · extend ? (all_blank sig n).
+
+(*
+definition R_move_to_blank_L ≝ λsig,n,i,t1,t2.
+(current ? t1 = None ? → 
+  t2 = midtape (multi_sig sig n) (left ? t1) (all_blank …) (right ? t1)) ∧
+∀ls,a,rs.t1 = midtape ? ls a rs → 
+  ((no_blank sig n i a = false) ∧ t2 = t1) ∨
+  (∃b,ls1,ls2.
+    (no_blank sig n i b = false) ∧ 
+    (∀j.j ≤n → to_blank_i ?? j (ls1@b::ls2) = to_blank_i ?? j ls) ∧
+    t2 = midtape ? ls2 b ((reverse ? (a::ls1))@rs)). 
+*)
+
+definition R_move_to_blank_L ≝ λsig,n,i,t1,t2.
+(current ? t1 = None ? → 
+  t2 = midtape (multi_sig sig n) (left ? t1) (all_blank …) (right ? t1)) ∧
+∀ls,a,rs.
+  t1 = midtape (multi_sig sig n) ls a rs → 
+  regular_i sig n (a::ls) i →
+  (∀j. j ≠ i → regular_trace … a ls rs j) →
+  (∃b,ls1,ls2.
+    (regular_i sig n (ls1@b::ls2) i) ∧ 
+    (∀j. j ≠ i → regular_trace … 
+      (hd ? (ls1@b::ls2) (all_blank …)) (tail ? (ls1@b::ls2)) rs j) ∧ 
+    (no_blank sig n i b = false) ∧ 
+    (hd (multi_sig sig n) (ls1@[b]) (all_blank …) = a) ∧ (* not implied by the next fact *)
+    (∀j.j ≤n → to_blank_i ?? j (ls1@b::ls2) = to_blank_i ?? j (a::ls)) ∧
+    t2 = midtape ? ls2 b ((reverse ? ls1)@rs)).
+
+theorem sem_move_to_blank_L: ∀sig,n,i. 
+  move_to_blank_L sig n i  ⊨ R_move_to_blank_L sig n i.
+#sig #n #i 
+@(sem_seq_app ?????? 
+  (ssem_move_until_L ? (no_blank sig n i)) (sem_extend ? (all_blank sig n)))
+#tin #tout * #t1 * * #Ht1a #Ht1b * #Ht2a #Ht2b %
+  [#Hcur >(Ht1a Hcur) in Ht2a; /2 by /
+  |#ls #a #rs #Htin #Hreg #Hreg2 -Ht1a cases (Ht1b … Htin)
+    [* #Hnb #Ht1 -Ht1b -Ht2a >Ht1 in Ht2b; >Htin #H 
+     %{a} %{[ ]} %{ls} 
+     %[%[%[%[%[@Hreg|@Hreg2]|@Hnb]|//]|//]|@H normalize % #H1 destruct (H1)]
+    |* 
+    [(* we find the blank *)
+     * #ls1 * #b * #ls2 * * * #H1 #H2 #H3 #Ht1
+     >Ht1 in Ht2b; #Hout -Ht1b
+     %{b} %{(a::ls1)} %{ls2} 
+     %[%[%[%[%[>H1 in Hreg; #H @H 
+              |#j #jneqi whd in match (hd ???); whd in match (tail ??);
+               <H1 @(Hreg2 j jneqi)]|@H2] |//]|>H1 //]
+      |@Hout normalize % normalize #H destruct (H)
+      ]
+    |* #b * #lss * * #H1 #H2 #Ht1 -Ht1b >Ht1 in Ht2a; 
+     whd in match (left ??); whd in match (right ??); #Hout
+     %{(all_blank …)} %{(lss@[b])} %{[]}
+     %[%[%[%[%[<H2 @regular_extend // 
+              |<H2 #j #jneqi whd in match (hd ???); whd in match (tail ??); 
+               @regular_trace_extl @Hreg2 //]
+            |whd in match (no_blank ????); >blank_all_blank //]
+          |<H2 //]
+        |#j #lejn <H2 @sym_eq @to_blank_i_ext]
+      |>reverse_append >reverse_single @Hout normalize // 
+      ]
+    ]
+  ]
+qed.
+
+(******************************************************************************)
+   
+definition shift_i_L ≝ λsig,n,i.
+   ncombf_r (multi_sig …) (shift_i sig n i) (all_blank sig n) ·
+   mti sig n i · 
+   extend ? (all_blank sig n).
+   
+definition R_shift_i_L ≝ λsig,n,i,t1,t2.
+    (∀a,ls,rs. 
+      t1 = midtape ? ls a rs  → 
+      ((∃rs1,b,rs2,a1,rss.
+        rs = rs1@b::rs2 ∧ 
+        nth i ? (vec … b) (blank ?) = (blank ?) ∧
+        (∀x. mem ? x rs1 → nth i ? (vec … x) (blank ?) ≠ (blank ?)) ∧
+        shift_l sig n i (a::rs1) (a1::rss) ∧
+        t2 = midtape (multi_sig sig n) ((reverse ? (a1::rss))@ls) b rs2) ∨
+      (∃b,rss. 
+        (∀x. mem ? x rs → nth i ? (vec … x) (blank ?) ≠ (blank ?)) ∧
+        shift_l sig n i (a::rs) (rss@[b]) ∧
+        t2 = midtape (multi_sig sig n) 
+          ((reverse ? (rss@[b]))@ls) (all_blank sig n) [ ]))).
+
+definition R_shift_i_L_new ≝ λsig,n,i,t1,t2.
+  (∀a,ls,rs. 
+   t1 = midtape ? ls a rs  → 
+   ∃rs1,b,rs2,rss.
+      b = hd ? rs2 (all_blank sig n) ∧
+      nth i ? (vec … b) (blank ?) = (blank ?) ∧
+      rs = rs1@rs2 ∧ 
+      (∀x. mem ? x rs1 → nth i ? (vec … x) (blank ?) ≠ (blank ?)) ∧
+      shift_l sig n i (a::rs1) rss ∧
+      t2 = midtape (multi_sig sig n) ((reverse ? rss)@ls) b (tail ? rs2)). 
+          
+theorem sem_shift_i_L: ∀sig,n,i. shift_i_L sig n i  ⊨ R_shift_i_L sig n i.
+#sig #n #i 
+@(sem_seq_app ?????? 
+  (sem_ncombf_r (multi_sig sig n) (shift_i sig n i)(all_blank sig n))
+   (sem_seq ????? (ssem_mti sig n i) 
+    (sem_extend ? (all_blank sig n))))
+#tin #tout * #t1 * * #Ht1a #Ht1b * #t2 * * #Ht2a #Ht2b * #Htout1 #Htout2
+#a #ls #rs cases rs
+  [#Htin %2 %{(shift_i sig n i a (all_blank sig n))} %{[ ]} 
+   %[%[#x @False_ind | @daemon]
+    |lapply (Ht1a … Htin) -Ht1a -Ht1b #Ht1 
+     lapply (Ht2a … Ht1) -Ht2a -Ht2b #Ht2 >Ht2 in Htout1; 
+     >Ht1 whd in match (left ??); whd in match (right ??); #Htout @Htout // 
+    ]
+  |#a1 #rs1 #Htin 
+   lapply (Ht1b … Htin) -Ht1a -Ht1b #Ht1 
+   lapply (Ht2b … Ht1) -Ht2a -Ht2b *
+    [(* a1 is blank *) * #H1 #H2 %1
+     %{[ ]} %{a1} %{rs1} %{(shift_i sig n i a a1)} %{[ ]}
+     %[%[%[%[// |//] |#x @False_ind] | @daemon]
+      |>Htout2 [>H2 >reverse_single @Ht1 |>H2 >Ht1 normalize % #H destruct (H)]
+      ]
+    |*
+    [* #rs10 * #b * #rs2 * #rss * * * * #H1 #H2 #H3 #H4
+     #Ht2 %1 
+     %{(a1::rs10)} %{b} %{rs2} %{(shift_i sig n i a a1)} %{rss}
+     %[%[%[%[>H1 //|//] |@H3] |@daemon ]
+      |>reverse_cons >associative_append 
+       >H2 in Htout2; #Htout >Htout [@Ht2| >Ht2 normalize % #H destruct (H)]  
+      ]
+    |* #b * #rss * * #H1 #H2 
+     #Ht2 %2
+     %{(shift_i sig n i b (all_blank sig n))} %{(shift_i sig n i a a1::rss)}
+     %[%[@H1 |@daemon ]
+      |>Ht2 in Htout1; #Htout >Htout //
+       whd in match (left ??); whd in match (right ??);
+       >reverse_append >reverse_single >associative_append  >reverse_cons
+       >associative_append // 
+       ]
+     ]
+   ]
+ ]
+qed.
+ 
+theorem sem_shift_i_L_new: ∀sig,n,i. 
+  shift_i_L sig n i  ⊨ R_shift_i_L_new sig n i.
+#sig #n #i 
+@(Realize_to_Realize … (sem_shift_i_L sig n i))
+#t1 #t2 #H #a #ls #rs #Ht1 lapply (H a ls rs Ht1) *
+  [* #rs1 * #b * #rs2 * #a1 * #rss * * * * #H1 #H2 #H3 #H4 #Ht2
+   %{rs1} %{b} %{(b::rs2)} %{(a1::rss)} 
+   %[%[%[%[%[//|@H2]|@H1]|@H3]|@H4] | whd in match (tail ??); @Ht2]
+  |* #b * #rss * * #H1 #H2 #Ht2
+   %{rs} %{(all_blank sig n)} %{[]} %{(rss@[b])} 
+   %[%[%[%[%[//|@blank_all_blank]|//]|@H1]|@H2] | whd in match (tail ??); @Ht2]
+  ]
+qed.
+   
+
+(*******************************************************************************
+The following machine implements a full move of for a trace: we reach the left 
+border, shift the i-th trace and come back to the head position. *)  
+
+(* this exclude the possibility that traces do not overlap: the head must 
+remain inside all traces *)
+
+definition mtiL ≝ λsig,n,i.
+   move_to_blank_L sig n i · 
+   shift_i_L sig n i ·
+   move_until ? L (no_head sig n). 
+   
+definition Rmtil ≝ λsig,n,i,t1,t2.
+  ∀ls,a,rs. 
+   t1 = midtape (multi_sig sig n) ls a rs → 
+   nth n ? (vec … a) (blank ?) = head ? →  
+   (∀i.regular_trace sig n a ls rs i) → 
+   (* next: we cannot be on rightof on trace i *)
+   (nth i ? (vec … a) (blank ?) = (blank ?) 
+     → nth i ? (vec … (hd ? rs (all_blank …))) (blank ?) ≠ (blank ?)) →
+   no_head_in … ls →   
+   no_head_in … rs  → 
+   (∃ls1,a1,rs1.
+     t2 = midtape (multi_sig …) ls1 a1 rs1 ∧
+     (∀i.regular_trace … a1 ls1 rs1 i) ∧
+     (∀j. j ≤ n → j ≠ i → to_blank_i ? n j (a1::ls1) = to_blank_i ? n j (a::ls)) ∧
+     (∀j. j ≤ n → j ≠ i → to_blank_i ? n j rs1 = to_blank_i ? n j rs) ∧
+     (to_blank_i ? n i ls1 = to_blank_i ? n i (a::ls)) ∧
+     (to_blank_i ? n i (a1::rs1)) = to_blank_i ? n i rs).
+
+theorem sem_Rmtil: ∀sig,n,i. i < n → mtiL sig n i  ⊨ Rmtil sig n i.
+#sig #n #i #lt_in
+@(sem_seq_app ?????? 
+  (sem_move_to_blank_L … )
+   (sem_seq ????? (sem_shift_i_L_new …)
+    (ssem_move_until_L ? (no_head sig n))))
+#tin #tout * #t1 * * #_ #Ht1 * #t2 * #Ht2 * #_ #Htout
+(* we start looking into Rmitl *)
+#ls #a #rs #Htin (* tin is a midtape *)
+#Hhead #Hreg #no_rightof #Hnohead_ls #Hnohead_rs 
+cut (regular_i sig n (a::ls) i)
+  [cases (Hreg i) * // 
+   cases (true_or_false (nth i ? (vec … a) (blank ?) == (blank ?))) #Htest
+    [#_ @daemon (* absurd, since hd rs non e' blank *)
+    |#H #_ @daemon]] #Hreg1
+lapply (Ht1 … Htin Hreg1 ?) [#j #_ @Hreg] -Ht1 -Htin
+* #b * #ls1 * #ls2 * * * * * #reg_ls1_i #reg_ls1_j #Hno_blankb #Hhead #Hls1 #Ht1
+lapply (Ht2 … Ht1) -Ht2 -Ht1 
+* #rs1 * #b0 * #rs2 * #rss * * * * * #Hb0 #Hb0blank #Hrs1 #Hrs1b #Hrss #Ht2
+(* we need to recover the position of the head of the emulated machine
+   that is the head of ls1. This is somewhere inside rs1 *) 
+cut (∃rs11. rs1 = (reverse ? ls1)@rs11)
+  [cut (ls1 = [ ] ∨ ∃aa,tlls1. ls1 = aa::tlls1)
+    [cases ls1 [%1 // | #aa #tlls1 %2 %{aa} %{tlls1} //]] *
+      [#H1ls1 %{rs1} >H1ls1 //
+      |* #aa * #tlls1 #H1ls1 >H1ls1 in Hrs1; 
+       cut (aa = a) [>H1ls1 in Hls1; #H @(to_blank_hd … H)] #eqaa >eqaa  
+       #Hrs1_aux cases (compare_append … (sym_eq … Hrs1_aux)) #l *
+        [* #H1 #H2 %{l} @H1
+        |(* this is absurd : if l is empty, the case is as before.
+           if l is not empty then it must start with a blank, since it is the
+           first character in rs2. But in this case we would have a blank 
+           inside ls1=a::tls1 that is absurd *)
+          @daemon
+        ]]]   
+   * #rs11 #H1
+cut (rs = rs11@rs2)
+  [@(injective_append_l … (reverse … ls1)) >Hrs1 <associative_append <H1 //] #H2
+lapply (Htout … Ht2) -Htout -Ht2 *
+  [(* the current character on trace i holds the head-mark.
+      The case is absurd, since b0 is the head of rs2, that is a sublist of rs, 
+      and the head-mark is not in rs *)
+   * #H3 @False_ind @(absurd (nth n ? (vec … b0) (blank sig) = head ?)) 
+     [@(\P ?) @injective_notb @H3 ]
+   @Hnohead_rs >H2 >trace_append @mem_append_l2 
+   lapply Hb0 cases rs2 
+    [whd in match (hd ???); #H >H in H3; whd in match (no_head ???); 
+     >all_blank_n normalize -H #H destruct (H); @False_ind
+    |#c #r #H4 %1 >H4 //
+    ]
+  |* 
+  [(* we reach the head position *)
+   (* cut (trace sig n j (a1::ls20)=trace sig n j (ls1@b::ls2)) *)
+   * #ls10 * #a1 * #ls20 * * * #Hls20 #Ha1 #Hnh #Htout
+   cut (∀j.j ≠ i →
+      trace sig n j (reverse (multi_sig sig n) rs1@b::ls2) = 
+      trace sig n j (ls10@a1::ls20))
+    [#j #ineqj >append_cons <reverse_cons >trace_def <map_append <reverse_map
+     lapply (trace_shift_neq …lt_in ? (sym_not_eq … ineqj) … Hrss) [//] #Htr
+     <(trace_def …  (b::rs1)) <Htr >reverse_map >map_append @eq_f @Hls20 ] 
+   #Htracej
+   cut (trace sig n i (reverse (multi_sig sig n) (rs1@[b0])@ls2) = 
+        trace sig n i (ls10@a1::ls20))
+    [>trace_def <map_append <reverse_map <map_append <(trace_def … [b0]) 
+     cut (trace sig n i [b0] = [blank ?]) [@daemon] #Hcut >Hcut
+     lapply (trace_shift … lt_in … Hrss) [//] whd in match (tail ??); #Htr <Htr
+     >reverse_map >map_append <trace_def <Hls20 % 
+    ] 
+   #Htracei
+   cut (∀j. j ≠ i →
+      (trace sig n j (reverse (multi_sig sig n) rs11) = trace sig n j ls10) ∧ 
+      (trace sig n j (ls1@b::ls2) = trace sig n j (a1::ls20)))
+   [@daemon (* si fa 
+     #j #ineqj @(first_P_to_eq ? (λx. x ≠ head ?))
+      [lapply (Htracej … ineqj) >trace_def in ⊢ (%→?); <map_append 
+       >trace_def in ⊢ (%→?); <map_append #H @H  
+      | *) ] #H2
+  cut ((trace sig n i (b0::reverse ? rs11) = trace sig n i (ls10@[a1])) ∧ 
+      (trace sig n i (ls1@ls2) = trace sig n i ls20))
+   [>H1 in Htracei; >reverse_append >reverse_single >reverse_append 
+     >reverse_reverse >associative_append >associative_append
+     @daemon
+    ] #H3    
+  cut (∀j. j ≠ i → 
+    trace sig n j (reverse (multi_sig sig n) ls10@rs2) = trace sig n j rs)
+    [#j #jneqi @(injective_append_l … (trace sig n j (reverse ? ls1)))
+     >map_append >map_append >Hrs1 >H1 >associative_append 
+     <map_append <map_append in ⊢ (???%); @eq_f 
+     <map_append <map_append @eq_f2 // @sym_eq 
+     <(reverse_reverse … rs11) <reverse_map <reverse_map in ⊢ (???%);
+     @eq_f @(proj1 … (H2 j jneqi))] #Hrs_j
+   %{ls20} %{a1} %{(reverse ? (b0::ls10)@tail (multi_sig sig n) rs2)}
+   %[%[%[%[%[@Htout
+    |#j cases (decidable_eq_nat j i)
+      [#eqji >eqji (* by cases wether a1 is blank *)
+       @daemon
+      |#jneqi lapply (reg_ls1_j … jneqi) #H4 
+       >reverse_cons >associative_append >Hb0 @regular_cons_hd_rs
+       @(eq_trace_to_regular … H4)
+        [<hd_trace >(proj2 … (H2 … jneqi)) >hd_trace %
+        |<tail_trace >(proj2 … (H2 … jneqi)) >tail_trace %
+        |@sym_eq @Hrs_j //
+        ]
+      ]]
+    |#j #lejn #jneqi <(Hls1 … lejn) 
+     >to_blank_i_def >to_blank_i_def @eq_f @sym_eq @(proj2 … (H2 j jneqi))]
+    |#j #lejn #jneqi >reverse_cons >associative_append >Hb0
+     <to_blank_hd_cons >to_blank_i_def >to_blank_i_def @eq_f @Hrs_j //]
+    |<(Hls1 i) [2:@lt_to_le //] 
+     lapply (all_blank_after_blank … reg_ls1_i) 
+       [@(\P ?) @daemon] #allb_ls2
+     whd in match (to_blank_i ????); <(proj2 … H3)
+     @daemon ]
+    |>reverse_cons >associative_append  
+     cut (to_blank_i sig n i rs = to_blank_i sig n i (rs11@[b0])) [@daemon] 
+     #Hcut >Hcut >(to_blank_i_chop  … b0 (a1::reverse …ls10)) [2: @Hb0blank]
+     >to_blank_i_def >to_blank_i_def @eq_f 
+     >trace_def >trace_def @injective_reverse >reverse_map >reverse_cons
+     >reverse_reverse >reverse_map >reverse_append >reverse_single @sym_eq
+     @(proj1 … H3)
+    ]
+  |(*we do not find the head: this is absurd *)
+   * #b1 * #lss * * #H2 @False_ind 
+   cut (∀x0. mem ? x0 (trace sig n n (b0::reverse ? rss@ls2)) → x0 ≠ head ?)
+     [@daemon] -H2 #H2
+   lapply (trace_shift_neq sig n i n … lt_in … Hrss)
+     [@lt_to_not_eq @lt_in | // ] 
+   #H3 @(absurd 
+        (nth n ? (vec … (hd ? (ls1@[b]) (all_blank sig n))) (blank ?) = head ?))
+     [>Hhead //
+     |@H2 >trace_def %2 <map_append @mem_append_l1 <reverse_map <trace_def 
+      >H3 >H1 >trace_def >reverse_map >reverse_cons >reverse_append 
+      >reverse_reverse >associative_append <map_append @mem_append_l2
+      cases ls1 [%1 % |#x #ll %1 %]
+     ]
+   ]
+ ]
+qed.
diff --git a/matita/matita/lib/turing/multi_to_mono/shift_trace_machines.ma b/matita/matita/lib/turing/multi_to_mono/shift_trace_aux.ma
similarity index 100%
rename from matita/matita/lib/turing/multi_to_mono/shift_trace_machines.ma
rename to matita/matita/lib/turing/multi_to_mono/shift_trace_aux.ma
-- 
2.39.2