src/ZF/UNITY/SubstAx.ML
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     1 (*  Title:      ZF/UNITY/SubstAx.ML
       
     2     ID:         $Id$
       
     3     Author:     Sidi O Ehmety, Computer Laboratory
       
     4     Copyright   2001  University of Cambridge
       
     5 
       
     6 LeadsTo relation, restricted to the set of reachable states.
       
     7 
       
     8 *)
       
     9 
       
    10 
       
    11 (*Resembles the previous definition of LeadsTo*)
       
    12 
       
    13 Goalw [LeadsTo_def]
       
    14      "A LeadsTo B = \
       
    15 \ {F:program. F : (reachable(F) Int A) leadsTo (reachable(F) Int B) & \
       
    16 \    A:condition & B:condition}";
       
    17 by (blast_tac (claset() addDs [psp_stable2, leadsToD, constrainsD2] 
       
    18                         addIs [leadsTo_weaken]) 1);
       
    19 qed "LeadsTo_eq_leadsTo";
       
    20 
       
    21 Goalw [LeadsTo_def]
       
    22 "F: A LeadsTo B ==> F:program & A:condition & B:condition";
       
    23 by (Blast_tac 1);
       
    24 qed "LeadsToD";
       
    25 
       
    26 (*** Specialized laws for handling invariants ***)
       
    27 
       
    28 (** Conjoining an Always property **)
       
    29 Goal "[| F : Always(INV); A:condition |] ==> \
       
    30 \  (F : (INV Int A) LeadsTo A') <-> (F : A LeadsTo A')";
       
    31 by (asm_full_simp_tac
       
    32     (simpset() addsimps [LeadsTo_def, Always_eq_includes_reachable,
       
    33               Int_absorb2, Int_assoc RS sym, leadsToD]) 1);
       
    34 qed "Always_LeadsTo_pre";
       
    35 
       
    36 Goal "[| F : Always(INV); A':condition |] \
       
    37   \ ==> (F : A LeadsTo (INV Int A')) <-> (F : A LeadsTo A')";
       
    38 by (asm_full_simp_tac
       
    39     (simpset() addsimps [LeadsTo_eq_leadsTo, Always_eq_includes_reachable, 
       
    40           Int_absorb2, Int_assoc RS sym,leadsToD]) 1);
       
    41 qed "Always_LeadsTo_post";
       
    42 
       
    43 (* Like 'Always_LeadsTo_pre RS iffD1', but with premises in the good order *)
       
    44 Goal "[| F:Always(C); F : (C Int A) LeadsTo A'; A:condition |] \
       
    45 \ ==> F: A LeadsTo A'";
       
    46 by (blast_tac (claset() addIs [Always_LeadsTo_pre RS iffD1]) 1);
       
    47 qed "Always_LeadsToI";
       
    48 
       
    49 (* Like 'Always_LeadsTo_post RS iffD2', but with premises in the good order *)
       
    50 Goal
       
    51 "[| F : Always(C);  F : A LeadsTo A'; A':condition |] \
       
    52 \  ==> F : A LeadsTo (C Int A')";
       
    53 by (blast_tac (claset() addIs [Always_LeadsTo_post RS iffD2]) 1);
       
    54 qed "Always_LeadsToD";
       
    55 
       
    56 (*** Introduction rules: Basis, Trans, Union ***)
       
    57 
       
    58 Goal "F : A leadsTo B ==> F : A LeadsTo B";
       
    59 by (simp_tac (simpset() addsimps [LeadsTo_def]) 1);
       
    60 by (blast_tac (claset() addIs [leadsTo_weaken_L]
       
    61                         addDs [leadsToD]) 1);
       
    62 qed "leadsTo_imp_LeadsTo";
       
    63 
       
    64 Goal "[| F : A LeadsTo B;  F : B LeadsTo C |] ==> F : A LeadsTo C";
       
    65 by (full_simp_tac (simpset() addsimps [LeadsTo_eq_leadsTo]) 1);
       
    66 by (blast_tac (claset() addIs [leadsTo_Trans]) 1);
       
    67 qed "LeadsTo_Trans";
       
    68 
       
    69 Goalw [LeadsTo_def]
       
    70      "[| ALL A:S. F : A LeadsTo B; F:program; B:condition |] \
       
    71 \ ==> F : Union(S) LeadsTo B";
       
    72 by Auto_tac;
       
    73 by (stac Int_Union_Union2 1);
       
    74 by (blast_tac (claset() addIs [leadsTo_UN]) 1);
       
    75 bind_thm("LeadsTo_Union", ballI RS result());
       
    76 
       
    77 
       
    78 (*** Derived rules ***)
       
    79 
       
    80 Goalw [LeadsTo_def] 
       
    81 "[| F:program; A:condition |] ==>F : A LeadsTo state";
       
    82 by (blast_tac (claset() addIs [leadsTo_state]) 1);
       
    83 qed "LeadsTo_state";
       
    84 Addsimps [LeadsTo_state];
       
    85 
       
    86 (*Useful with cancellation, disjunction*)
       
    87 Goal "F : A LeadsTo (A' Un A') ==> F : A LeadsTo A'";
       
    88 by (asm_full_simp_tac (simpset() addsimps Un_ac) 1);
       
    89 qed "LeadsTo_Un_duplicate";
       
    90 
       
    91 Goal "F : A LeadsTo (A' Un C Un C) ==> F : A LeadsTo (A' Un C)";
       
    92 by (asm_full_simp_tac (simpset() addsimps Un_ac) 1);
       
    93 qed "LeadsTo_Un_duplicate2";
       
    94 
       
    95 Goal "[| ALL i:I. F : A(i) LeadsTo B; F:program; B:condition |] \
       
    96 \  ==> F : (UN i:I. A(i)) LeadsTo B";
       
    97 by (simp_tac (simpset() addsimps [Int_Union_Union]) 1);
       
    98 by (blast_tac (claset() addIs [LeadsTo_Union]) 1);
       
    99 bind_thm("LeadsTo_UN", ballI RS result());
       
   100 
       
   101 (*Binary union introduction rule*)
       
   102 Goal "[| F : A LeadsTo C; F : B LeadsTo C |] ==> F : (A Un B) LeadsTo C";
       
   103 by (stac Un_eq_Union 1);
       
   104 by (blast_tac (claset() addIs [LeadsTo_Union] 
       
   105                         addDs [LeadsToD]) 1);
       
   106 qed "LeadsTo_Un";
       
   107 
       
   108 (*Lets us look at the starting state*)
       
   109 Goal "[| ALL s:A. F : {s} LeadsTo B; F:program; B:condition |]\
       
   110 \  ==> F : A LeadsTo B";
       
   111 by (stac (UN_singleton RS sym) 1 THEN rtac LeadsTo_UN 1);
       
   112 by (REPEAT(Blast_tac 1));
       
   113 bind_thm("single_LeadsTo_I", ballI RS result());
       
   114 
       
   115 Goal "[| A <= B; B:condition; F:program |] ==> F : A LeadsTo B";
       
   116 by (subgoal_tac "A:condition" 1);
       
   117 by (force_tac (claset(), 
       
   118          simpset() addsimps [condition_def]) 2);
       
   119 by (simp_tac (simpset() addsimps [LeadsTo_def]) 1);
       
   120 by (blast_tac (claset() addIs [subset_imp_leadsTo]) 1);
       
   121 qed "subset_imp_LeadsTo";
       
   122 
       
   123 bind_thm ("empty_LeadsTo", empty_subsetI RS subset_imp_LeadsTo);
       
   124 Addsimps [empty_LeadsTo];
       
   125 
       
   126 Goal "[| F : A LeadsTo A';  A' <= B'; B':condition |] ==> F : A LeadsTo B'";
       
   127 by (full_simp_tac (simpset() addsimps [LeadsTo_def]) 1);
       
   128 by (blast_tac (claset() addIs [leadsTo_weaken_R]) 1);
       
   129 qed_spec_mp "LeadsTo_weaken_R";
       
   130 
       
   131 
       
   132 Goal "[| F : A LeadsTo A';  B <= A |]  \
       
   133 \     ==> F : B LeadsTo A'";
       
   134 by (subgoal_tac "B:condition" 1);
       
   135 by (force_tac (claset() addSDs [LeadsToD],
       
   136                simpset() addsimps [condition_def]) 2);
       
   137 by (full_simp_tac (simpset() addsimps [LeadsTo_def]) 1);
       
   138 by (blast_tac (claset() addIs [leadsTo_weaken_L]) 1);
       
   139 qed_spec_mp "LeadsTo_weaken_L";
       
   140 
       
   141 Goal "[| F : A LeadsTo A';   \
       
   142 \        B  <= A;   A' <= B'; B':condition |] \
       
   143 \     ==> F : B LeadsTo B'";
       
   144 by (blast_tac (claset() addIs [LeadsTo_weaken_R, 
       
   145                     LeadsTo_weaken_L, LeadsTo_Trans]) 1);
       
   146 qed "LeadsTo_weaken";
       
   147 
       
   148 Goal "[| F : Always(C);  F : A LeadsTo A';   \
       
   149 \        C Int B <= A;   C Int A' <= B'; B:condition; B':condition |] \
       
   150 \     ==> F : B LeadsTo B'";
       
   151 by (blast_tac (claset() 
       
   152       addDs [AlwaysD2, LeadsToD, Always_LeadsToI]
       
   153       addIs [LeadsTo_weaken, Always_LeadsToD]) 1);
       
   154 qed "Always_LeadsTo_weaken";
       
   155 
       
   156 (** Two theorems for "proof lattices" **)
       
   157 
       
   158 Goal "F : A LeadsTo B ==> F:(A Un B) LeadsTo B";
       
   159 by (blast_tac (claset() 
       
   160          addIs [LeadsTo_Un, subset_imp_LeadsTo]
       
   161          addDs [LeadsToD]) 1);
       
   162 qed "LeadsTo_Un_post";
       
   163 
       
   164 Goal "[| F : A LeadsTo B;  F : B LeadsTo C |] \
       
   165 \     ==> F : (A Un B) LeadsTo C";
       
   166 by (blast_tac (claset() addIs [LeadsTo_Un, subset_imp_LeadsTo, 
       
   167                                LeadsTo_weaken_L, LeadsTo_Trans]
       
   168                         addDs [LeadsToD]) 1);
       
   169 qed "LeadsTo_Trans_Un";
       
   170 
       
   171 
       
   172 (** Distributive laws **)
       
   173 
       
   174 Goal "(F : (A Un B) LeadsTo C)  <-> (F : A LeadsTo C & F : B LeadsTo C)";
       
   175 by (blast_tac (claset() addIs [LeadsTo_Un, LeadsTo_weaken_L]) 1);
       
   176 qed "LeadsTo_Un_distrib";
       
   177 
       
   178 Goal "[| F:program; B:condition |] ==> \
       
   179 \ (F : (UN i:I. A(i)) LeadsTo B) <->  (ALL i : I. F : A(i) LeadsTo B)";
       
   180 by (blast_tac (claset() addIs [LeadsTo_UN, LeadsTo_weaken_L]) 1);
       
   181 qed "LeadsTo_UN_distrib";
       
   182 
       
   183 Goal "[| F:program; B:condition |] ==> \
       
   184 \ (F : Union(S) LeadsTo B)  <->  (ALL A : S. F : A LeadsTo B)";
       
   185 by (blast_tac (claset() addIs [LeadsTo_Union, LeadsTo_weaken_L]) 1);
       
   186 qed "LeadsTo_Union_distrib";
       
   187 
       
   188 (** More rules using the premise "Always INV" **)
       
   189 
       
   190 Goal "F : A Ensures B ==> F : A LeadsTo B";
       
   191 by (asm_full_simp_tac
       
   192     (simpset() addsimps [Ensures_def, LeadsTo_def, leadsTo_Basis]) 1);
       
   193 qed "LeadsTo_Basis";
       
   194 
       
   195 Goal "[| F : (A-B) Co (A Un B);  F : transient (A-B) |]   \
       
   196 \     ==> F : A Ensures B";
       
   197 by (asm_full_simp_tac
       
   198     (simpset() addsimps [Ensures_def, Constrains_eq_constrains]) 1);
       
   199 by (blast_tac (claset() addIs [ensuresI, constrains_weaken, 
       
   200                                transient_strengthen]
       
   201                         addDs [constrainsD2]) 1);
       
   202 qed "EnsuresI";
       
   203 
       
   204 Goal "[| F : Always(INV);      \
       
   205 \        F : (INV Int (A-A')) Co (A Un A'); \
       
   206 \        F : transient (INV Int (A-A')) |]   \
       
   207 \ ==> F : A LeadsTo A'";
       
   208 by (rtac Always_LeadsToI 1);
       
   209 by (assume_tac 1);
       
   210 by (blast_tac (claset() addDs [ConstrainsD]) 2);
       
   211 by (blast_tac (claset() addIs [EnsuresI, LeadsTo_Basis,
       
   212                                Always_ConstrainsD RS Constrains_weaken, 
       
   213                                transient_strengthen]
       
   214                         addDs [AlwaysD2, ConstrainsD]) 1);
       
   215 qed "Always_LeadsTo_Basis";
       
   216 
       
   217 (*Set difference: maybe combine with leadsTo_weaken_L??
       
   218   This is the most useful form of the "disjunction" rule*)
       
   219 Goal "[| F : (A-B) LeadsTo C;  F : (A Int B) LeadsTo C; \
       
   220 \ A:condition; B:condition |] \
       
   221 \     ==> F : A LeadsTo C";
       
   222 by (blast_tac (claset() addIs [LeadsTo_Un, LeadsTo_weaken]
       
   223                 addDs [LeadsToD]) 1);
       
   224 qed "LeadsTo_Diff";
       
   225 
       
   226 
       
   227 Goal "[| ALL i:I. F: A(i) LeadsTo A'(i); F:program |] \
       
   228 \     ==> F : (UN i:I. A(i)) LeadsTo (UN i:I. A'(i))";
       
   229 by (rtac LeadsTo_Union 1);
       
   230 by (ALLGOALS(Clarify_tac));
       
   231 by (blast_tac (claset() addDs [LeadsToD]) 2);
       
   232 by (blast_tac (claset()  addIs [LeadsTo_weaken_R]
       
   233                          addDs [LeadsToD]) 1);
       
   234 bind_thm ("LeadsTo_UN_UN", ballI RS result());
       
   235 
       
   236 
       
   237 (*Version with no index set*)
       
   238 Goal "[| ALL i. F: A(i) LeadsTo A'(i); F:program |] \
       
   239 \     ==> F : (UN i:I. A(i)) LeadsTo (UN i:I. A'(i))";
       
   240 by (blast_tac (claset() addIs [LeadsTo_UN_UN]) 1);
       
   241 qed "all_LeadsTo_UN_UN";
       
   242 
       
   243 bind_thm ("LeadsTo_UN_UN_noindex", allI RS all_LeadsTo_UN_UN);
       
   244 
       
   245 (*Binary union version*)
       
   246 Goal "[| F : A LeadsTo A'; F : B LeadsTo B' |] \
       
   247 \           ==> F : (A Un B) LeadsTo (A' Un B')";
       
   248 by (blast_tac (claset() 
       
   249         addIs [LeadsTo_Un, LeadsTo_weaken_R]
       
   250         addDs [LeadsToD]) 1);
       
   251 qed "LeadsTo_Un_Un";
       
   252 
       
   253 (** The cancellation law **)
       
   254 
       
   255 Goal "[| F : A LeadsTo (A' Un B); F : B LeadsTo B' |]    \
       
   256 \     ==> F : A LeadsTo (A' Un B')";
       
   257 by (blast_tac (claset() addIs [LeadsTo_Un_Un, 
       
   258                                subset_imp_LeadsTo, LeadsTo_Trans]
       
   259                     addDs [LeadsToD]) 1);
       
   260 qed "LeadsTo_cancel2";
       
   261 
       
   262 Goal "A Un (B - A) = A Un B";
       
   263 by Auto_tac;
       
   264 qed "Un_Diff";
       
   265 
       
   266 Goal "[| F : A LeadsTo (A' Un B); F : (B-A') LeadsTo B' |] \
       
   267 \     ==> F : A LeadsTo (A' Un B')";
       
   268 by (rtac LeadsTo_cancel2 1);
       
   269 by (assume_tac 2);
       
   270 by (asm_simp_tac (simpset() addsimps [Un_Diff]) 1);
       
   271 qed "LeadsTo_cancel_Diff2";
       
   272 
       
   273 Goal "[| F : A LeadsTo (B Un A'); F : B LeadsTo B' |] \
       
   274 \     ==> F : A LeadsTo (B' Un A')";
       
   275 by (asm_full_simp_tac (simpset() addsimps [Un_commute]) 1);
       
   276 by (blast_tac (claset() addSIs [LeadsTo_cancel2]) 1);
       
   277 qed "LeadsTo_cancel1";
       
   278 
       
   279 
       
   280 Goal "(B - A) Un A = B Un A";
       
   281 by Auto_tac;
       
   282 qed "Diff_Un2";
       
   283 
       
   284 Goal "[| F : A LeadsTo (B Un A'); F : (B-A') LeadsTo B' |] \
       
   285 \     ==> F : A LeadsTo (B' Un A')";
       
   286 by (rtac LeadsTo_cancel1 1);
       
   287 by (assume_tac 2);
       
   288 by (asm_simp_tac (simpset() addsimps [Diff_Un2]) 1);
       
   289 qed "LeadsTo_cancel_Diff1";
       
   290 
       
   291 
       
   292 (** The impossibility law **)
       
   293 
       
   294 (*The set "A" may be non-empty, but it contains no reachable states*)
       
   295 Goal "F : A LeadsTo 0 ==> F : Always (state -A)";
       
   296 by (full_simp_tac (simpset() 
       
   297            addsimps [LeadsTo_def,Always_eq_includes_reachable]) 1);
       
   298 by (Clarify_tac 1);
       
   299 by (forward_tac [reachableD] 1);
       
   300 by (auto_tac (claset() addSDs [leadsTo_empty],
       
   301               simpset() addsimps [condition_def]));
       
   302 qed "LeadsTo_empty";
       
   303 
       
   304 (** PSP: Progress-Safety-Progress **)
       
   305 
       
   306 (*Special case of PSP: Misra's "stable conjunction"*)
       
   307 Goal "[| F : A LeadsTo A';  F : Stable(B) |] \
       
   308 \     ==> F : (A Int B) LeadsTo (A' Int B)";
       
   309 by (forward_tac [StableD2] 1);
       
   310 by (rotate_tac ~1 1);
       
   311 by (asm_full_simp_tac
       
   312     (simpset() addsimps [LeadsTo_eq_leadsTo, Stable_eq_stable]) 1);
       
   313 by (Clarify_tac 1);
       
   314 by (dtac psp_stable 1);
       
   315 by (assume_tac 1);
       
   316 by (asm_full_simp_tac (simpset() addsimps (Int_absorb::Int_ac)) 1);
       
   317 qed "PSP_Stable";
       
   318 
       
   319 Goal "[| F : A LeadsTo A'; F : Stable(B) |] \
       
   320 \     ==> F : (B Int A) LeadsTo (B Int A')";
       
   321 by (asm_simp_tac (simpset() addsimps PSP_Stable::Int_ac) 1);
       
   322 qed "PSP_Stable2";
       
   323 
       
   324 Goal "[| F : A LeadsTo A'; F : B Co B' |] \
       
   325 \     ==> F : (A Int B') LeadsTo ((A' Int B) Un (B' - B))";
       
   326 by (full_simp_tac
       
   327     (simpset() addsimps [LeadsTo_def, Constrains_eq_constrains]) 1);
       
   328 by (blast_tac (claset() addDs [psp] addIs [leadsTo_weaken]) 1);
       
   329 qed "PSP";
       
   330 
       
   331 Goal "[| F : A LeadsTo A'; F : B Co B' |] \
       
   332 \     ==> F : (B' Int A) LeadsTo ((B Int A') Un (B' - B))";
       
   333 by (asm_simp_tac (simpset() addsimps PSP::Int_ac) 1);
       
   334 qed "PSP2";
       
   335 
       
   336 
       
   337 Goal
       
   338 "[| F : A LeadsTo A'; F : B Unless B' |] \
       
   339 \     ==> F : (A Int B) LeadsTo ((A' Int B) Un B')";
       
   340 by (forward_tac [LeadsToD] 1);
       
   341 by (forward_tac [UnlessD] 1);
       
   342 by (rewrite_goals_tac [Unless_def]);
       
   343 by (dtac PSP 1);
       
   344 by (assume_tac 1);
       
   345 by (blast_tac (claset() 
       
   346         addIs [LeadsTo_Diff, 
       
   347                LeadsTo_weaken, subset_imp_LeadsTo]) 1);
       
   348 qed "PSP_Unless";
       
   349 
       
   350 (*** Induction rules ***)
       
   351 
       
   352 (** Meta or object quantifier ????? **)
       
   353 Goal "[| wf(r);     \
       
   354 \        ALL m:I. F : (A Int f-``{m}) LeadsTo                     \
       
   355 \                           ((A Int f-``(converse(r) `` {m})) Un B); \
       
   356 \        field(r)<=I; A<=f-``I; F:program; A:condition; B:condition |] \
       
   357 \     ==> F : A LeadsTo B";
       
   358 by (full_simp_tac (simpset() addsimps [LeadsTo_eq_leadsTo]) 1);
       
   359 by Safe_tac;
       
   360 by (eres_inst_tac [("I", "I"), ("f", "f")] leadsTo_wf_induct 1);
       
   361 by (ALLGOALS(Clarify_tac));
       
   362 by (dres_inst_tac [("x", "m")] bspec 4);
       
   363 by Safe_tac;
       
   364 by (res_inst_tac [("A'", 
       
   365            "reachable(F) Int (A Int f -``(converse(r)``{m}) Un B)")]  
       
   366         leadsTo_weaken_R 4);
       
   367 by (asm_simp_tac (simpset() addsimps [Int_assoc]) 4);
       
   368 by (asm_simp_tac (simpset() addsimps [Int_assoc]) 5);
       
   369 by (REPEAT(Blast_tac 1));
       
   370 qed "LeadsTo_wf_induct";
       
   371 
       
   372 
       
   373 
       
   374 Goal "[| ALL m:nat. F:(A Int f-``{m}) LeadsTo ((A Int f-``lessThan(m,nat)) Un B); \
       
   375 \     A<=f-``nat; F:program; A:condition; B:condition |] \
       
   376 \     ==> F : A LeadsTo B";
       
   377 by (res_inst_tac [("A1", "nat"), ("I", "nat")] (wf_less_than RS LeadsTo_wf_induct) 1);
       
   378 by (ALLGOALS(asm_full_simp_tac 
       
   379           (simpset() addsimps [nat_less_than_field])));
       
   380 by (Clarify_tac 1);
       
   381 by (ALLGOALS(asm_full_simp_tac 
       
   382     (simpset() addsimps [rewrite_rule [vimage_def] Image_inverse_less_than])));
       
   383 qed "LessThan_induct";
       
   384 
       
   385 
       
   386 (****** 
       
   387  To be ported ??? I am not sure.
       
   388 
       
   389   integ_0_le_induct
       
   390   LessThan_bounded_induct
       
   391   GreaterThan_bounded_induct
       
   392 
       
   393 *****)
       
   394 
       
   395 (*** Completion: Binary and General Finite versions ***)
       
   396 
       
   397 Goal "[| F : A LeadsTo (A' Un C);  F : A' Co (A' Un C); \
       
   398 \        F : B LeadsTo (B' Un C);  F : B' Co (B' Un C) |] \
       
   399 \     ==> F : (A Int B) LeadsTo ((A' Int B') Un C)";
       
   400 by (full_simp_tac
       
   401     (simpset() addsimps [LeadsTo_eq_leadsTo, Constrains_eq_constrains, 
       
   402                          Int_Un_distrib2 RS sym]) 1);
       
   403 by Safe_tac;
       
   404 by (REPEAT(Blast_tac 2));
       
   405 by (blast_tac (claset() addIs [completion, leadsTo_weaken]) 1);
       
   406 qed "Completion";
       
   407 
       
   408 
       
   409 Goal "[| I:Fin(X);F:program; C:condition |] \
       
   410 \     ==> (ALL i:I. F : (A(i)) LeadsTo (A'(i) Un C)) -->  \
       
   411 \         (ALL i:I. F : (A'(i)) Co (A'(i) Un C)) --> \
       
   412 \         F : (INT i:I. A(i)) LeadsTo ((INT i:I. A'(i)) Un C)";
       
   413 by (etac Fin_induct 1);
       
   414 by Auto_tac;
       
   415 by (case_tac "y=0" 1);
       
   416 by Auto_tac;
       
   417 by (etac not_emptyE 1);
       
   418 by (subgoal_tac "Inter(cons(A(x), RepFun(y, A)))= A(x) Int Inter(RepFun(y,A)) &\
       
   419                \ Inter(cons(A'(x), RepFun(y, A')))= A'(x) Int Inter(RepFun(y,A'))" 1);
       
   420 by (Blast_tac 2);
       
   421 by (Asm_simp_tac 1);
       
   422 by (rtac Completion 1);
       
   423 by (subgoal_tac "Inter(RepFun(y, A')) Un C = (INT x:RepFun(y, A'). x Un C)" 4);
       
   424 by (Blast_tac 5);
       
   425 by (Asm_simp_tac 4);
       
   426 by (rtac Constrains_INT 4);
       
   427 by (REPEAT(Blast_tac 1));
       
   428 val lemma = result();
       
   429 
       
   430 
       
   431 val prems = Goal
       
   432      "[| I:Fin(X); !!i. i:I ==> F : A(i) LeadsTo (A'(i) Un C); \
       
   433 \        !!i. i:I ==> F : A'(i) Co (A'(i) Un C); \
       
   434 \        F:program; C:condition |]   \
       
   435 \     ==> F : (INT i:I. A(i)) LeadsTo ((INT i:I. A'(i)) Un C)";
       
   436 by (blast_tac (claset() addIs (lemma RS mp RS mp)::prems) 1);
       
   437 qed "Finite_completion";
       
   438 
       
   439 Goalw [Stable_def]
       
   440      "[| F : A LeadsTo A';  F : Stable(A');   \
       
   441 \        F : B LeadsTo B';  F : Stable(B') |] \
       
   442 \   ==> F : (A Int B) LeadsTo (A' Int B')";
       
   443 by (res_inst_tac [("C1", "0")] (Completion RS LeadsTo_weaken_R) 1);
       
   444 by (REPEAT(blast_tac (claset() addDs [LeadsToD,ConstrainsD]) 5));
       
   445 by (ALLGOALS(Asm_full_simp_tac));
       
   446 qed "Stable_completion";
       
   447 
       
   448 
       
   449 val prems = Goalw [Stable_def]
       
   450      "[| I:Fin(X); \
       
   451 \        ALL i:I. F : A(i) LeadsTo A'(i); \
       
   452 \        ALL i:I.  F: Stable(A'(i));   F:program  |] \
       
   453 \     ==> F : (INT i:I. A(i)) LeadsTo (INT i:I. A'(i))";
       
   454 by (subgoal_tac "(INT i:I. A'(i)):condition" 1);
       
   455 by (blast_tac (claset() addDs  [LeadsToD,ConstrainsD]) 2);
       
   456 by (res_inst_tac [("C1", "0")] (Finite_completion RS LeadsTo_weaken_R) 1);
       
   457 by (assume_tac 7);
       
   458 by (ALLGOALS(Asm_full_simp_tac));
       
   459 by (ALLGOALS (Blast_tac));
       
   460 qed "Finite_stable_completion";
       
   461 
       
   462 
       
   463 (*proves "ensures/leadsTo" properties when the program is specified*)
       
   464 fun ensures_tac sact = 
       
   465     SELECT_GOAL
       
   466       (EVERY [REPEAT (Always_Int_tac 1),
       
   467               etac Always_LeadsTo_Basis 1 
       
   468                   ORELSE   (*subgoal may involve LeadsTo, leadsTo or ensures*)
       
   469                   REPEAT (ares_tac [LeadsTo_Basis, leadsTo_Basis,
       
   470                                     EnsuresI, ensuresI] 1),
       
   471               (*now there are two subgoals: co & transient*)
       
   472               simp_tac (simpset() addsimps !program_defs_ref) 2,
       
   473               res_inst_tac [("act", sact)] transientI 2,
       
   474                  (*simplify the command's domain*)
       
   475               simp_tac (simpset() addsimps [domain_def]) 3, 
       
   476               (* proving the domain part *)
       
   477              Clarify_tac 3, dtac swap 3, Force_tac 4,
       
   478              rtac ReplaceI 3, Force_tac 3, Force_tac 4,
       
   479              Asm_full_simp_tac 3, rtac conjI 3, Simp_tac 4,
       
   480              REPEAT (rtac update_type2 3),
       
   481              constrains_tac 1,
       
   482              ALLGOALS Clarify_tac,
       
   483              ALLGOALS (asm_full_simp_tac 
       
   484             (simpset() addsimps [condition_def])),
       
   485             ALLGOALS Clarify_tac]);
       
   486