#alpha #c #t @(ex_intro … 2) @ex_intro
[|% [% |#ls #c #rs #Ht >Ht % ] ]
qed.
-
+
+definition R_write_strong ≝ λalpha,c,t1,t2.
+ t2 = midtape alpha (left ? t1) c (right ? t1).
+
+lemma sem_write_strong : ∀alpha,c.Realize ? (write alpha c) (R_write_strong alpha c).
+#alpha #c #t @(ex_intro … 2) @ex_intro
+ [|% [% |cases t normalize // ] ]
+qed.
+
+(***************************** replace a with f a *****************************)
+
+definition writef ≝ λalpha,f.
+ mk_TM alpha write_states
+ (λp.let 〈q,a〉 ≝ p in
+ match pi1 … q with
+ [ O ⇒ 〈wr1,Some ? (f a),N〉
+ | S _ ⇒ 〈wr1,None ?,N〉 ])
+ wr0 (λx.x == wr1).
+
+definition R_writef ≝ λalpha,f,t1,t2.
+ ∀c. current ? t1 = c →
+ t2 = midtape alpha (left ? t1) (f c) (right ? t1).
+
+lemma sem_writef : ∀alpha,f.
+ writef alpha f ⊨ R_writef alpha f.
+#alpha #f #t @(ex_intro … 2) @ex_intro
+ [|% [% |cases t normalize // ] ]
+qed.
+
(******************** moves the head one step to the right ********************)
definition move_states ≝ initN 2.
[#b #rs #H destruct | #a #b #ls #rs #H destruct normalize //
]
]
-qed.
\ No newline at end of file
+qed.
+
+(********************************** combine ***********************************)
+(* replace the content x of a cell with a combiation f(x,y) of x and the content
+y of the adiacent cell *)
+
+definition combf_states : FinSet → FinSet ≝
+ λalpha:FinSet.FinProd (initN 4) alpha.
+
+definition combf0 : initN 4 ≝ mk_Sig ?? 0 (leb_true_to_le 1 4 (refl …)).
+definition combf1 : initN 4 ≝ mk_Sig ?? 1 (leb_true_to_le 2 4 (refl …)).
+definition combf2 : initN 4 ≝ mk_Sig ?? 2 (leb_true_to_le 3 4 (refl …)).
+definition combf3 : initN 4 ≝ mk_Sig ?? 3 (leb_true_to_le 4 4 (refl …)).
+
+definition combf_r ≝
+ λalpha:FinSet.λf.λfoo:alpha.
+ mk_TM alpha (combf_states alpha)
+ (λp.let 〈q,a〉 ≝ p in
+ let 〈q',b〉 ≝ q in
+ let q' ≝ pi1 nat (λi.i<4) q' in
+ match a with
+ [ None ⇒ 〈〈combf3,foo〉,None ?,N〉 (* if tape is empty then stop *)
+ | Some a' ⇒
+ match q' with
+ [ O ⇒ (* q0 *) 〈〈combf1,a'〉,Some ? a',R〉 (* save in register and move R *)
+ | S q' ⇒ match q' with
+ [ O ⇒ (* q1 *) 〈〈combf2,f b a'〉,Some ? a',L〉
+ (* combine in register and move L *)
+ | S q' ⇒ match q' with
+ [ O ⇒ (* q2 *) 〈〈combf3,foo〉,Some ? b,R〉
+ (* copy from register and move R *)
+ | S q' ⇒ (* q3 *) 〈〈combf3,foo〉,None ?,N〉 (* final state *)
+ ]
+ ]
+ ]])
+ 〈combf0,foo〉
+ (λq.\fst q == combf3).
+
+definition Rcombf_r ≝
+ λalpha,f,t1,t2.
+ (∀b,ls.
+ t1 = midtape alpha ls b [ ] →
+ t2 = rightof ? b ls) ∧
+ (∀a,b,ls,rs.
+ t1 = midtape alpha ls b (a::rs) →
+ t2 = midtape alpha ((f b a)::ls) a rs).
+
+lemma sem_combf_r : ∀alpha,f,foo.
+ combf_r alpha f foo ⊨ Rcombf_r alpha f.
+#alpha #f #foo *
+ [@(ex_intro ?? 2) @(ex_intro … (mk_config ?? 〈combf3,foo〉 (niltape ?)))
+ % [% |% [#b #ls | #a #b #ls #rs] #H destruct]
+ |#l0 #lt0 @(ex_intro ?? 2) @(ex_intro … (mk_config ?? 〈combf3,foo〉 (leftof ? l0 lt0)))
+ % [% | % [#b #ls | #a #b #ls #rs] #H destruct]
+ |#r0 #rt0 @(ex_intro ?? 2) @(ex_intro … (mk_config ?? 〈combf3,foo〉 (rightof ? r0 rt0)))
+ % [% |% [#b #ls | #a #b #ls #rs] #H destruct]
+ | #lt #c #rt @(ex_intro ?? 4) cases rt
+ [@ex_intro [|% [ % | %
+ [#b #ls #H destruct normalize // |#a #b #ls #rs #H destruct]]]
+ |#r0 #rt0 @ex_intro [| % [ % | %
+ [#b #ls #H destruct | #a #b #ls #rs #H destruct normalize //
+ ]
+ ]
+qed.
+
+definition combf_l ≝
+ λalpha:FinSet.λf.λfoo:alpha.
+ mk_TM alpha (combf_states alpha)
+ (λp.let 〈q,a〉 ≝ p in
+ let 〈q',b〉 ≝ q in
+ let q' ≝ pi1 nat (λi.i<4) q' in
+ match a with
+ [ None ⇒ 〈〈combf3,foo〉,None ?,N〉 (* if tape is empty then stop *)
+ | Some a' ⇒
+ match q' with
+ [ O ⇒ (* q0 *) 〈〈combf1,a'〉,Some ? a',L〉 (* save in register and move R *)
+ | S q' ⇒ match q' with
+ [ O ⇒ (* q1 *) 〈〈combf2,f b a'〉,Some ? a',R〉
+ (* combine in register and move L *)
+ | S q' ⇒ match q' with
+ [ O ⇒ (* q2 *) 〈〈combf3,foo〉,Some ? b,L〉
+ (* copy from register and move R *)
+ | S q' ⇒ (* q3 *) 〈〈combf3,foo〉,None ?,N〉 (* final state *)
+ ]
+ ]
+ ]])
+ 〈combf0,foo〉
+ (λq.\fst q == combf3).
+
+definition Rcombf_l ≝
+ λalpha,f,t1,t2.
+ (∀b,rs.
+ t1 = midtape alpha [ ] b rs →
+ t2 = leftof ? b rs) ∧
+ (∀a,b,ls,rs.
+ t1 = midtape alpha (a::ls) b rs →
+ t2 = midtape alpha ls a ((f b a)::rs)).
+
+lemma sem_combf_l : ∀alpha,f,foo.
+ combf_l alpha f foo ⊨ Rcombf_l alpha f.
+#alpha #f #foo *
+ [@(ex_intro ?? 2) @(ex_intro … (mk_config ?? 〈combf3,foo〉 (niltape ?)))
+ % [% |% [#b #ls | #a #b #ls #rs] #H destruct]
+ |#l0 #lt0 @(ex_intro ?? 2) @(ex_intro … (mk_config ?? 〈combf3,foo〉 (leftof ? l0 lt0)))
+ % [% | % [#b #ls | #a #b #ls #rs] #H destruct]
+ |#r0 #rt0 @(ex_intro ?? 2) @(ex_intro … (mk_config ?? 〈combf3,foo〉 (rightof ? r0 rt0)))
+ % [% |% [#b #ls | #a #b #ls #rs] #H destruct]
+ | #lt #c #rt @(ex_intro ?? 4) cases lt
+ [@ex_intro [|% [ % | %
+ [#b #ls #H destruct normalize // |#a #b #ls #rs #H destruct]]]
+ |#r0 #rt0 @ex_intro [| % [ % | %
+ [#b #ls #H destruct | #a #b #ls #rs #H destruct normalize //
+ ]
+ ]
+qed.
+
+(********************************* new_combine ********************************)
+(* replace the content x of a cell with a combiation f(x,y) of x and the content
+y of the adiacent cell; if there is no adjacent cell, combines with a default
+value foo *)
+
+definition ncombf_r ≝
+ λalpha:FinSet.λf.λfoo:alpha.
+ mk_TM alpha (combf_states alpha)
+ (λp.let 〈q,a〉 ≝ p in
+ let 〈q',b〉 ≝ q in
+ let q' ≝ pi1 nat (λi.i<4) q' in
+ match a with
+ [ None ⇒ if (eqb q' 1)then (* if on right cell, combine in register and move L *)
+ 〈〈combf2,f b foo〉,None ?,L〉
+ else 〈〈combf3,foo〉,None ?,N〉 (* else stop *)
+ | Some a' ⇒
+ match q' with
+ [ O ⇒ (* q0 *) 〈〈combf1,a'〉,Some ? a',R〉 (* save in register and move R *)
+ | S q' ⇒ match q' with
+ [ O ⇒ (* q1 *) 〈〈combf2,f b a'〉,Some ? a',L〉
+ (* combine in register and move L *)
+ | S q' ⇒ match q' with
+ [ O ⇒ (* q2 *) 〈〈combf3,foo〉,Some ? b,R〉
+ (* copy from register and move R *)
+ | S q' ⇒ (* q3 *) 〈〈combf3,foo〉,None ?,N〉 (* final state *)
+ ]
+ ]
+ ]])
+ 〈combf0,foo〉
+ (λq.\fst q == combf3).
+
+definition Rncombf_r ≝
+ λalpha,f,foo,t1,t2.
+ (∀b,ls.
+ t1 = midtape alpha ls b [ ] →
+ t2 = rightof ? (f b foo) ls) ∧
+ (∀a,b,ls,rs.
+ t1 = midtape alpha ls b (a::rs) →
+ t2 = midtape alpha ((f b a)::ls) a rs).
+
+lemma sem_ncombf_r : ∀alpha,f,foo.
+ ncombf_r alpha f foo ⊨ Rncombf_r alpha f foo.
+#alpha #f #foo *
+ [@(ex_intro ?? 2) @(ex_intro … (mk_config ?? 〈combf3,foo〉 (niltape ?)))
+ % [% |% [#b #ls | #a #b #ls #rs] #H destruct]
+ |#l0 #lt0 @(ex_intro ?? 2) @(ex_intro … (mk_config ?? 〈combf3,foo〉 (leftof ? l0 lt0)))
+ % [% | % [#b #ls | #a #b #ls #rs] #H destruct]
+ |#r0 #rt0 @(ex_intro ?? 2) @(ex_intro … (mk_config ?? 〈combf3,foo〉 (rightof ? r0 rt0)))
+ % [% |% [#b #ls | #a #b #ls #rs] #H destruct]
+ | #lt #c #rt @(ex_intro ?? 4) cases rt
+ [@ex_intro [|% [ % | %
+ [#b #ls #H destruct normalize // |#a #b #ls #rs #H destruct]]]
+ |#r0 #rt0 @ex_intro [| % [ % | %
+ [#b #ls #H destruct | #a #b #ls #rs #H destruct normalize //
+ ]
+ ]
+qed.
+
+definition ncombf_l ≝
+ λalpha:FinSet.λf.λfoo:alpha.
+ mk_TM alpha (combf_states alpha)
+ (λp.let 〈q,a〉 ≝ p in
+ let 〈q',b〉 ≝ q in
+ let q' ≝ pi1 nat (λi.i<4) q' in
+ match a with
+ [ None ⇒ if (eqb q' 1)then
+ (* if on left cell, combine in register and move R *)
+ 〈〈combf2,f b foo〉,None ?,R〉
+ else 〈〈combf3,foo〉,None ?,N〉 (* else stop *)
+ | Some a' ⇒
+ match q' with
+ [ O ⇒ (* q0 *) 〈〈combf1,a'〉,Some ? a',L〉 (* save in register and move R *)
+ | S q' ⇒ match q' with
+ [ O ⇒ (* q1 *) 〈〈combf2,f b a'〉,Some ? a',R〉
+ (* combine in register and move L *)
+ | S q' ⇒ match q' with
+ [ O ⇒ (* q2 *) 〈〈combf3,foo〉,Some ? b,L〉
+ (* copy from register and move R *)
+ | S q' ⇒ (* q3 *) 〈〈combf3,foo〉,None ?,N〉 (* final state *)
+ ]
+ ]
+ ]])
+ 〈combf0,foo〉
+ (λq.\fst q == combf3).
+
+definition Rncombf_l ≝
+ λalpha,f,foo,t1,t2.
+ (∀b,rs.
+ t1 = midtape alpha [ ] b rs →
+ t2 = leftof ? (f b foo) rs) ∧
+ (∀a,b,ls,rs.
+ t1 = midtape alpha (a::ls) b rs →
+ t2 = midtape alpha ls a ((f b a)::rs)).
+
+lemma sem_ncombf_l : ∀alpha,f,foo.
+ ncombf_l alpha f foo ⊨ Rncombf_l alpha f foo.
+#alpha #f #foo *
+ [@(ex_intro ?? 2) @(ex_intro … (mk_config ?? 〈combf3,foo〉 (niltape ?)))
+ % [% |% [#b #ls | #a #b #ls #rs] #H destruct]
+ |#l0 #lt0 @(ex_intro ?? 2) @(ex_intro … (mk_config ?? 〈combf3,foo〉 (leftof ? l0 lt0)))
+ % [% | % [#b #ls | #a #b #ls #rs] #H destruct]
+ |#r0 #rt0 @(ex_intro ?? 2) @(ex_intro … (mk_config ?? 〈combf3,foo〉 (rightof ? r0 rt0)))
+ % [% |% [#b #ls | #a #b #ls #rs] #H destruct]
+ | #lt #c #rt @(ex_intro ?? 4) cases lt
+ [@ex_intro [|% [ % | %
+ [#b #ls #H destruct normalize // |#a #b #ls #rs #H destruct]]]
+ |#r0 #rt0 @ex_intro [| % [ % | %
+ [#b #ls #H destruct | #a #b #ls #rs #H destruct normalize //
+ ]
+ ]
+qed.