src/HOL/Set.ML
 author paulson Wed Mar 03 11:15:18 1999 +0100 (1999-03-03) changeset 6301 08245f5a436d parent 6291 2c3f72d9f5d1 child 6394 3d9fd50fcc43 permissions -rw-r--r--
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```     1 (*  Title:      HOL/set
```
```     2     ID:         \$Id\$
```
```     3     Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
```
```     4     Copyright   1991  University of Cambridge
```
```     5
```
```     6 Set theory for higher-order logic.  A set is simply a predicate.
```
```     7 *)
```
```     8
```
```     9 section "Relating predicates and sets";
```
```    10
```
```    11 Addsimps [Collect_mem_eq];
```
```    12 AddIffs  [mem_Collect_eq];
```
```    13
```
```    14 Goal "P(a) ==> a : {x. P(x)}";
```
```    15 by (Asm_simp_tac 1);
```
```    16 qed "CollectI";
```
```    17
```
```    18 Goal "a : {x. P(x)} ==> P(a)";
```
```    19 by (Asm_full_simp_tac 1);
```
```    20 qed "CollectD";
```
```    21
```
```    22 val [prem] = Goal "[| !!x. (x:A) = (x:B) |] ==> A = B";
```
```    23 by (rtac (prem RS ext RS arg_cong RS box_equals) 1);
```
```    24 by (rtac Collect_mem_eq 1);
```
```    25 by (rtac Collect_mem_eq 1);
```
```    26 qed "set_ext";
```
```    27
```
```    28 val [prem] = Goal "[| !!x. P(x)=Q(x) |] ==> {x. P(x)} = {x. Q(x)}";
```
```    29 by (rtac (prem RS ext RS arg_cong) 1);
```
```    30 qed "Collect_cong";
```
```    31
```
```    32 val CollectE = make_elim CollectD;
```
```    33
```
```    34 AddSIs [CollectI];
```
```    35 AddSEs [CollectE];
```
```    36
```
```    37
```
```    38 section "Bounded quantifiers";
```
```    39
```
```    40 val prems = Goalw [Ball_def]
```
```    41     "[| !!x. x:A ==> P(x) |] ==> ! x:A. P(x)";
```
```    42 by (REPEAT (ares_tac (prems @ [allI,impI]) 1));
```
```    43 qed "ballI";
```
```    44
```
```    45 Goalw [Ball_def] "[| ! x:A. P(x);  x:A |] ==> P(x)";
```
```    46 by (Blast_tac 1);
```
```    47 qed "bspec";
```
```    48
```
```    49 val major::prems = Goalw [Ball_def]
```
```    50     "[| ! x:A. P(x);  P(x) ==> Q;  x~:A ==> Q |] ==> Q";
```
```    51 by (rtac (major RS spec RS impCE) 1);
```
```    52 by (REPEAT (eresolve_tac prems 1));
```
```    53 qed "ballE";
```
```    54
```
```    55 (*Takes assumptions ! x:A.P(x) and a:A; creates assumption P(a)*)
```
```    56 fun ball_tac i = etac ballE i THEN contr_tac (i+1);
```
```    57
```
```    58 AddSIs [ballI];
```
```    59 AddEs  [ballE];
```
```    60 (* gives better instantiation for bound: *)
```
```    61 claset_ref() := claset() addWrapper ("bspec", fn tac2 =>
```
```    62 			 (dtac bspec THEN' atac) APPEND' tac2);
```
```    63
```
```    64 (*Normally the best argument order: P(x) constrains the choice of x:A*)
```
```    65 Goalw [Bex_def] "[| P(x);  x:A |] ==> ? x:A. P(x)";
```
```    66 by (Blast_tac 1);
```
```    67 qed "bexI";
```
```    68
```
```    69 (*The best argument order when there is only one x:A*)
```
```    70 Goalw [Bex_def] "[| x:A;  P(x) |] ==> ? x:A. P(x)";
```
```    71 by (Blast_tac 1);
```
```    72 qed "rev_bexI";
```
```    73
```
```    74 qed_goal "bexCI" Set.thy
```
```    75    "[| ! x:A. ~P(x) ==> P(a);  a:A |] ==> ? x:A. P(x)" (fn prems =>
```
```    76   [ (rtac classical 1),
```
```    77     (REPEAT (ares_tac (prems@[bexI,ballI,notI,notE]) 1))  ]);
```
```    78
```
```    79 val major::prems = Goalw [Bex_def]
```
```    80     "[| ? x:A. P(x);  !!x. [| x:A; P(x) |] ==> Q  |] ==> Q";
```
```    81 by (rtac (major RS exE) 1);
```
```    82 by (REPEAT (eresolve_tac (prems @ [asm_rl,conjE]) 1));
```
```    83 qed "bexE";
```
```    84
```
```    85 AddIs  [bexI];
```
```    86 AddSEs [bexE];
```
```    87
```
```    88 (*Trival rewrite rule*)
```
```    89 Goal "(! x:A. P) = ((? x. x:A) --> P)";
```
```    90 by (simp_tac (simpset() addsimps [Ball_def]) 1);
```
```    91 qed "ball_triv";
```
```    92
```
```    93 (*Dual form for existentials*)
```
```    94 Goal "(? x:A. P) = ((? x. x:A) & P)";
```
```    95 by (simp_tac (simpset() addsimps [Bex_def]) 1);
```
```    96 qed "bex_triv";
```
```    97
```
```    98 Addsimps [ball_triv, bex_triv];
```
```    99
```
```   100 (** Congruence rules **)
```
```   101
```
```   102 val prems = Goalw [Ball_def]
```
```   103     "[| A=B;  !!x. x:B ==> P(x) = Q(x) |] ==> \
```
```   104 \    (! x:A. P(x)) = (! x:B. Q(x))";
```
```   105 by (asm_simp_tac (simpset() addsimps prems) 1);
```
```   106 qed "ball_cong";
```
```   107
```
```   108 val prems = Goalw [Bex_def]
```
```   109     "[| A=B;  !!x. x:B ==> P(x) = Q(x) |] ==> \
```
```   110 \    (? x:A. P(x)) = (? x:B. Q(x))";
```
```   111 by (asm_simp_tac (simpset() addcongs [conj_cong] addsimps prems) 1);
```
```   112 qed "bex_cong";
```
```   113
```
```   114 Addcongs [ball_cong,bex_cong];
```
```   115
```
```   116 section "Subsets";
```
```   117
```
```   118 val prems = Goalw [subset_def] "(!!x. x:A ==> x:B) ==> A <= B";
```
```   119 by (REPEAT (ares_tac (prems @ [ballI]) 1));
```
```   120 qed "subsetI";
```
```   121
```
```   122 (*Map the type ('a set => anything) to just 'a.
```
```   123   For overloading constants whose first argument has type "'a set" *)
```
```   124 fun overload_1st_set s = Blast.overloaded (s, HOLogic.dest_setT o domain_type);
```
```   125
```
```   126 (*While (:) is not, its type must be kept
```
```   127   for overloading of = to work.*)
```
```   128 Blast.overloaded ("op :", domain_type);
```
```   129
```
```   130 overload_1st_set "Ball";		(*need UNION, INTER also?*)
```
```   131 overload_1st_set "Bex";
```
```   132
```
```   133 (*Image: retain the type of the set being expressed*)
```
```   134 Blast.overloaded ("op ``", domain_type);
```
```   135
```
```   136 (*Rule in Modus Ponens style*)
```
```   137 Goalw [subset_def] "[| A <= B;  c:A |] ==> c:B";
```
```   138 by (Blast_tac 1);
```
```   139 qed "subsetD";
```
```   140
```
```   141 (*The same, with reversed premises for use with etac -- cf rev_mp*)
```
```   142 qed_goal "rev_subsetD" Set.thy "[| c:A;  A <= B |] ==> c:B"
```
```   143  (fn prems=>  [ (REPEAT (resolve_tac (prems@[subsetD]) 1)) ]);
```
```   144
```
```   145 (*Converts A<=B to x:A ==> x:B*)
```
```   146 fun impOfSubs th = th RSN (2, rev_subsetD);
```
```   147
```
```   148 qed_goal "contra_subsetD" Set.thy "!!c. [| A <= B; c ~: B |] ==> c ~: A"
```
```   149  (fn prems=>  [ (REPEAT (eresolve_tac [asm_rl, contrapos, subsetD] 1)) ]);
```
```   150
```
```   151 qed_goal "rev_contra_subsetD" Set.thy "!!c. [| c ~: B;  A <= B |] ==> c ~: A"
```
```   152  (fn prems=>  [ (REPEAT (eresolve_tac [asm_rl, contrapos, subsetD] 1)) ]);
```
```   153
```
```   154 (*Classical elimination rule*)
```
```   155 val major::prems = Goalw [subset_def]
```
```   156     "[| A <= B;  c~:A ==> P;  c:B ==> P |] ==> P";
```
```   157 by (rtac (major RS ballE) 1);
```
```   158 by (REPEAT (eresolve_tac prems 1));
```
```   159 qed "subsetCE";
```
```   160
```
```   161 (*Takes assumptions A<=B; c:A and creates the assumption c:B *)
```
```   162 fun set_mp_tac i = etac subsetCE i  THEN  mp_tac i;
```
```   163
```
```   164 AddSIs [subsetI];
```
```   165 AddEs  [subsetD, subsetCE];
```
```   166
```
```   167 qed_goal "subset_refl" Set.thy "A <= (A::'a set)"
```
```   168  (fn _=> [Fast_tac 1]);		(*Blast_tac would try order_refl and fail*)
```
```   169
```
```   170 Goal "[| A<=B;  B<=C |] ==> A<=(C::'a set)";
```
```   171 by (Blast_tac 1);
```
```   172 qed "subset_trans";
```
```   173
```
```   174
```
```   175 section "Equality";
```
```   176
```
```   177 (*Anti-symmetry of the subset relation*)
```
```   178 Goal "[| A <= B;  B <= A |] ==> A = (B::'a set)";
```
```   179 by (rtac set_ext 1);
```
```   180 by (blast_tac (claset() addIs [subsetD]) 1);
```
```   181 qed "subset_antisym";
```
```   182 val equalityI = subset_antisym;
```
```   183
```
```   184 AddSIs [equalityI];
```
```   185
```
```   186 (* Equality rules from ZF set theory -- are they appropriate here? *)
```
```   187 Goal "A = B ==> A<=(B::'a set)";
```
```   188 by (etac ssubst 1);
```
```   189 by (rtac subset_refl 1);
```
```   190 qed "equalityD1";
```
```   191
```
```   192 Goal "A = B ==> B<=(A::'a set)";
```
```   193 by (etac ssubst 1);
```
```   194 by (rtac subset_refl 1);
```
```   195 qed "equalityD2";
```
```   196
```
```   197 val prems = Goal
```
```   198     "[| A = B;  [| A<=B; B<=(A::'a set) |] ==> P |]  ==>  P";
```
```   199 by (resolve_tac prems 1);
```
```   200 by (REPEAT (resolve_tac (prems RL [equalityD1,equalityD2]) 1));
```
```   201 qed "equalityE";
```
```   202
```
```   203 val major::prems = Goal
```
```   204     "[| A = B;  [| c:A; c:B |] ==> P;  [| c~:A; c~:B |] ==> P |]  ==>  P";
```
```   205 by (rtac (major RS equalityE) 1);
```
```   206 by (REPEAT (contr_tac 1 ORELSE eresolve_tac ([asm_rl,subsetCE]@prems) 1));
```
```   207 qed "equalityCE";
```
```   208
```
```   209 (*Lemma for creating induction formulae -- for "pattern matching" on p
```
```   210   To make the induction hypotheses usable, apply "spec" or "bspec" to
```
```   211   put universal quantifiers over the free variables in p. *)
```
```   212 val prems = Goal
```
```   213     "[| p:A;  !!z. z:A ==> p=z --> R |] ==> R";
```
```   214 by (rtac mp 1);
```
```   215 by (REPEAT (resolve_tac (refl::prems) 1));
```
```   216 qed "setup_induction";
```
```   217
```
```   218
```
```   219 section "The universal set -- UNIV";
```
```   220
```
```   221 qed_goalw "UNIV_I" Set.thy [UNIV_def] "x : UNIV"
```
```   222   (fn _ => [rtac CollectI 1, rtac TrueI 1]);
```
```   223
```
```   224 Addsimps [UNIV_I];
```
```   225 AddIs    [UNIV_I];  (*unsafe makes it less likely to cause problems*)
```
```   226
```
```   227 qed_goal "subset_UNIV" Set.thy "A <= UNIV"
```
```   228   (fn _ => [rtac subsetI 1, rtac UNIV_I 1]);
```
```   229
```
```   230 (** Eta-contracting these two rules (to remove P) causes them to be ignored
```
```   231     because of their interaction with congruence rules. **)
```
```   232
```
```   233 Goalw [Ball_def] "Ball UNIV P = All P";
```
```   234 by (Simp_tac 1);
```
```   235 qed "ball_UNIV";
```
```   236
```
```   237 Goalw [Bex_def] "Bex UNIV P = Ex P";
```
```   238 by (Simp_tac 1);
```
```   239 qed "bex_UNIV";
```
```   240 Addsimps [ball_UNIV, bex_UNIV];
```
```   241
```
```   242
```
```   243 section "The empty set -- {}";
```
```   244
```
```   245 qed_goalw "empty_iff" Set.thy [empty_def] "(c : {}) = False"
```
```   246  (fn _ => [ (Blast_tac 1) ]);
```
```   247
```
```   248 Addsimps [empty_iff];
```
```   249
```
```   250 qed_goal "emptyE" Set.thy "!!a. a:{} ==> P"
```
```   251  (fn _ => [Full_simp_tac 1]);
```
```   252
```
```   253 AddSEs [emptyE];
```
```   254
```
```   255 qed_goal "empty_subsetI" Set.thy "{} <= A"
```
```   256  (fn _ => [ (Blast_tac 1) ]);
```
```   257
```
```   258 (*One effect is to delete the ASSUMPTION {} <= A*)
```
```   259 AddIffs [empty_subsetI];
```
```   260
```
```   261 qed_goal "equals0I" Set.thy "[| !!y. y:A ==> False |] ==> A={}"
```
```   262  (fn [prem]=>
```
```   263   [ (blast_tac (claset() addIs [prem RS FalseE]) 1) ]);
```
```   264
```
```   265 (*Use for reasoning about disjointness: A Int B = {} *)
```
```   266 qed_goal "equals0D" Set.thy "!!a. A={} ==> a ~: A"
```
```   267  (fn _ => [ (Blast_tac 1) ]);
```
```   268
```
```   269 AddDs [equals0D, sym RS equals0D];
```
```   270
```
```   271 Goalw [Ball_def] "Ball {} P = True";
```
```   272 by (Simp_tac 1);
```
```   273 qed "ball_empty";
```
```   274
```
```   275 Goalw [Bex_def] "Bex {} P = False";
```
```   276 by (Simp_tac 1);
```
```   277 qed "bex_empty";
```
```   278 Addsimps [ball_empty, bex_empty];
```
```   279
```
```   280 Goal "UNIV ~= {}";
```
```   281 by (blast_tac (claset() addEs [equalityE]) 1);
```
```   282 qed "UNIV_not_empty";
```
```   283 AddIffs [UNIV_not_empty];
```
```   284
```
```   285
```
```   286
```
```   287 section "The Powerset operator -- Pow";
```
```   288
```
```   289 qed_goalw "Pow_iff" Set.thy [Pow_def] "(A : Pow(B)) = (A <= B)"
```
```   290  (fn _ => [ (Asm_simp_tac 1) ]);
```
```   291
```
```   292 AddIffs [Pow_iff];
```
```   293
```
```   294 qed_goalw "PowI" Set.thy [Pow_def] "!!A B. A <= B ==> A : Pow(B)"
```
```   295  (fn _ => [ (etac CollectI 1) ]);
```
```   296
```
```   297 qed_goalw "PowD" Set.thy [Pow_def] "!!A B. A : Pow(B)  ==>  A<=B"
```
```   298  (fn _=> [ (etac CollectD 1) ]);
```
```   299
```
```   300 val Pow_bottom = empty_subsetI RS PowI;        (* {}: Pow(B) *)
```
```   301 val Pow_top = subset_refl RS PowI;             (* A : Pow(A) *)
```
```   302
```
```   303
```
```   304 section "Set complement";
```
```   305
```
```   306 qed_goalw "Compl_iff" Set.thy [Compl_def] "(c : -A) = (c~:A)"
```
```   307  (fn _ => [ (Blast_tac 1) ]);
```
```   308
```
```   309 Addsimps [Compl_iff];
```
```   310
```
```   311 val prems = Goalw [Compl_def] "[| c:A ==> False |] ==> c : -A";
```
```   312 by (REPEAT (ares_tac (prems @ [CollectI,notI]) 1));
```
```   313 qed "ComplI";
```
```   314
```
```   315 (*This form, with negated conclusion, works well with the Classical prover.
```
```   316   Negated assumptions behave like formulae on the right side of the notional
```
```   317   turnstile...*)
```
```   318 Goalw [Compl_def] "c : -A ==> c~:A";
```
```   319 by (etac CollectD 1);
```
```   320 qed "ComplD";
```
```   321
```
```   322 val ComplE = make_elim ComplD;
```
```   323
```
```   324 AddSIs [ComplI];
```
```   325 AddSEs [ComplE];
```
```   326
```
```   327
```
```   328 section "Binary union -- Un";
```
```   329
```
```   330 qed_goalw "Un_iff" Set.thy [Un_def] "(c : A Un B) = (c:A | c:B)"
```
```   331  (fn _ => [ Blast_tac 1 ]);
```
```   332
```
```   333 Addsimps [Un_iff];
```
```   334
```
```   335 Goal "c:A ==> c : A Un B";
```
```   336 by (Asm_simp_tac 1);
```
```   337 qed "UnI1";
```
```   338
```
```   339 Goal "c:B ==> c : A Un B";
```
```   340 by (Asm_simp_tac 1);
```
```   341 qed "UnI2";
```
```   342
```
```   343 (*Classical introduction rule: no commitment to A vs B*)
```
```   344 qed_goal "UnCI" Set.thy "(c~:B ==> c:A) ==> c : A Un B"
```
```   345  (fn prems=>
```
```   346   [ (Simp_tac 1),
```
```   347     (REPEAT (ares_tac (prems@[disjCI]) 1)) ]);
```
```   348
```
```   349 val major::prems = Goalw [Un_def]
```
```   350     "[| c : A Un B;  c:A ==> P;  c:B ==> P |] ==> P";
```
```   351 by (rtac (major RS CollectD RS disjE) 1);
```
```   352 by (REPEAT (eresolve_tac prems 1));
```
```   353 qed "UnE";
```
```   354
```
```   355 AddSIs [UnCI];
```
```   356 AddSEs [UnE];
```
```   357
```
```   358
```
```   359 section "Binary intersection -- Int";
```
```   360
```
```   361 qed_goalw "Int_iff" Set.thy [Int_def] "(c : A Int B) = (c:A & c:B)"
```
```   362  (fn _ => [ (Blast_tac 1) ]);
```
```   363
```
```   364 Addsimps [Int_iff];
```
```   365
```
```   366 Goal "[| c:A;  c:B |] ==> c : A Int B";
```
```   367 by (Asm_simp_tac 1);
```
```   368 qed "IntI";
```
```   369
```
```   370 Goal "c : A Int B ==> c:A";
```
```   371 by (Asm_full_simp_tac 1);
```
```   372 qed "IntD1";
```
```   373
```
```   374 Goal "c : A Int B ==> c:B";
```
```   375 by (Asm_full_simp_tac 1);
```
```   376 qed "IntD2";
```
```   377
```
```   378 val [major,minor] = Goal
```
```   379     "[| c : A Int B;  [| c:A; c:B |] ==> P |] ==> P";
```
```   380 by (rtac minor 1);
```
```   381 by (rtac (major RS IntD1) 1);
```
```   382 by (rtac (major RS IntD2) 1);
```
```   383 qed "IntE";
```
```   384
```
```   385 AddSIs [IntI];
```
```   386 AddSEs [IntE];
```
```   387
```
```   388 section "Set difference";
```
```   389
```
```   390 qed_goalw "Diff_iff" Set.thy [set_diff_def] "(c : A-B) = (c:A & c~:B)"
```
```   391  (fn _ => [ (Blast_tac 1) ]);
```
```   392
```
```   393 Addsimps [Diff_iff];
```
```   394
```
```   395 qed_goal "DiffI" Set.thy "!!c. [| c : A;  c ~: B |] ==> c : A - B"
```
```   396  (fn _=> [ Asm_simp_tac 1 ]);
```
```   397
```
```   398 qed_goal "DiffD1" Set.thy "!!c. c : A - B ==> c : A"
```
```   399  (fn _=> [ (Asm_full_simp_tac 1) ]);
```
```   400
```
```   401 qed_goal "DiffD2" Set.thy "!!c. [| c : A - B;  c : B |] ==> P"
```
```   402  (fn _=> [ (Asm_full_simp_tac 1) ]);
```
```   403
```
```   404 qed_goal "DiffE" Set.thy "[| c : A - B;  [| c:A; c~:B |] ==> P |] ==> P"
```
```   405  (fn prems=>
```
```   406   [ (resolve_tac prems 1),
```
```   407     (REPEAT (ares_tac (prems RL [DiffD1, DiffD2 RS notI]) 1)) ]);
```
```   408
```
```   409 AddSIs [DiffI];
```
```   410 AddSEs [DiffE];
```
```   411
```
```   412
```
```   413 section "Augmenting a set -- insert";
```
```   414
```
```   415 qed_goalw "insert_iff" Set.thy [insert_def] "a : insert b A = (a=b | a:A)"
```
```   416  (fn _ => [Blast_tac 1]);
```
```   417
```
```   418 Addsimps [insert_iff];
```
```   419
```
```   420 qed_goal "insertI1" Set.thy "a : insert a B"
```
```   421  (fn _ => [Simp_tac 1]);
```
```   422
```
```   423 qed_goal "insertI2" Set.thy "!!a. a : B ==> a : insert b B"
```
```   424  (fn _=> [Asm_simp_tac 1]);
```
```   425
```
```   426 qed_goalw "insertE" Set.thy [insert_def]
```
```   427     "[| a : insert b A;  a=b ==> P;  a:A ==> P |] ==> P"
```
```   428  (fn major::prems=>
```
```   429   [ (rtac (major RS UnE) 1),
```
```   430     (REPEAT (eresolve_tac (prems @ [CollectE]) 1)) ]);
```
```   431
```
```   432 (*Classical introduction rule*)
```
```   433 qed_goal "insertCI" Set.thy "(a~:B ==> a=b) ==> a: insert b B"
```
```   434  (fn prems=>
```
```   435   [ (Simp_tac 1),
```
```   436     (REPEAT (ares_tac (prems@[disjCI]) 1)) ]);
```
```   437
```
```   438 AddSIs [insertCI];
```
```   439 AddSEs [insertE];
```
```   440
```
```   441 section "Singletons, using insert";
```
```   442
```
```   443 qed_goal "singletonI" Set.thy "a : {a}"
```
```   444  (fn _=> [ (rtac insertI1 1) ]);
```
```   445
```
```   446 Goal "b : {a} ==> b=a";
```
```   447 by (Blast_tac 1);
```
```   448 qed "singletonD";
```
```   449
```
```   450 bind_thm ("singletonE", make_elim singletonD);
```
```   451
```
```   452 qed_goal "singleton_iff" thy "(b : {a}) = (b=a)"
```
```   453 (fn _ => [Blast_tac 1]);
```
```   454
```
```   455 Goal "{a}={b} ==> a=b";
```
```   456 by (blast_tac (claset() addEs [equalityE]) 1);
```
```   457 qed "singleton_inject";
```
```   458
```
```   459 (*Redundant? But unlike insertCI, it proves the subgoal immediately!*)
```
```   460 AddSIs [singletonI];
```
```   461 AddSDs [singleton_inject];
```
```   462 AddSEs [singletonE];
```
```   463
```
```   464 Goal "{x. x=a} = {a}";
```
```   465 by (Blast_tac 1);
```
```   466 qed "singleton_conv";
```
```   467 Addsimps [singleton_conv];
```
```   468
```
```   469 Goal "{x. a=x} = {a}";
```
```   470 by (Blast_tac 1);
```
```   471 qed "singleton_conv2";
```
```   472 Addsimps [singleton_conv2];
```
```   473
```
```   474
```
```   475 section "Unions of families -- UNION x:A. B(x) is Union(B``A)";
```
```   476
```
```   477 Goalw [UNION_def] "(b: (UN x:A. B(x))) = (EX x:A. b: B(x))";
```
```   478 by (Blast_tac 1);
```
```   479 qed "UN_iff";
```
```   480
```
```   481 Addsimps [UN_iff];
```
```   482
```
```   483 (*The order of the premises presupposes that A is rigid; b may be flexible*)
```
```   484 Goal "[| a:A;  b: B(a) |] ==> b: (UN x:A. B(x))";
```
```   485 by Auto_tac;
```
```   486 qed "UN_I";
```
```   487
```
```   488 val major::prems = Goalw [UNION_def]
```
```   489     "[| b : (UN x:A. B(x));  !!x.[| x:A;  b: B(x) |] ==> R |] ==> R";
```
```   490 by (rtac (major RS CollectD RS bexE) 1);
```
```   491 by (REPEAT (ares_tac prems 1));
```
```   492 qed "UN_E";
```
```   493
```
```   494 AddIs  [UN_I];
```
```   495 AddSEs [UN_E];
```
```   496
```
```   497 val prems = Goalw [UNION_def]
```
```   498     "[| A=B;  !!x. x:B ==> C(x) = D(x) |] ==> \
```
```   499 \    (UN x:A. C(x)) = (UN x:B. D(x))";
```
```   500 by (asm_simp_tac (simpset() addsimps prems) 1);
```
```   501 qed "UN_cong";
```
```   502
```
```   503
```
```   504 section "Intersections of families -- INTER x:A. B(x) is Inter(B``A)";
```
```   505
```
```   506 Goalw [INTER_def] "(b: (INT x:A. B(x))) = (ALL x:A. b: B(x))";
```
```   507 by Auto_tac;
```
```   508 qed "INT_iff";
```
```   509
```
```   510 Addsimps [INT_iff];
```
```   511
```
```   512 val prems = Goalw [INTER_def]
```
```   513     "(!!x. x:A ==> b: B(x)) ==> b : (INT x:A. B(x))";
```
```   514 by (REPEAT (ares_tac ([CollectI,ballI] @ prems) 1));
```
```   515 qed "INT_I";
```
```   516
```
```   517 Goal "[| b : (INT x:A. B(x));  a:A |] ==> b: B(a)";
```
```   518 by Auto_tac;
```
```   519 qed "INT_D";
```
```   520
```
```   521 (*"Classical" elimination -- by the Excluded Middle on a:A *)
```
```   522 val major::prems = Goalw [INTER_def]
```
```   523     "[| b : (INT x:A. B(x));  b: B(a) ==> R;  a~:A ==> R |] ==> R";
```
```   524 by (rtac (major RS CollectD RS ballE) 1);
```
```   525 by (REPEAT (eresolve_tac prems 1));
```
```   526 qed "INT_E";
```
```   527
```
```   528 AddSIs [INT_I];
```
```   529 AddEs  [INT_D, INT_E];
```
```   530
```
```   531 val prems = Goalw [INTER_def]
```
```   532     "[| A=B;  !!x. x:B ==> C(x) = D(x) |] ==> \
```
```   533 \    (INT x:A. C(x)) = (INT x:B. D(x))";
```
```   534 by (asm_simp_tac (simpset() addsimps prems) 1);
```
```   535 qed "INT_cong";
```
```   536
```
```   537
```
```   538 section "Union";
```
```   539
```
```   540 Goalw [Union_def] "(A : Union(C)) = (EX X:C. A:X)";
```
```   541 by (Blast_tac 1);
```
```   542 qed "Union_iff";
```
```   543
```
```   544 Addsimps [Union_iff];
```
```   545
```
```   546 (*The order of the premises presupposes that C is rigid; A may be flexible*)
```
```   547 Goal "[| X:C;  A:X |] ==> A : Union(C)";
```
```   548 by Auto_tac;
```
```   549 qed "UnionI";
```
```   550
```
```   551 val major::prems = Goalw [Union_def]
```
```   552     "[| A : Union(C);  !!X.[| A:X;  X:C |] ==> R |] ==> R";
```
```   553 by (rtac (major RS UN_E) 1);
```
```   554 by (REPEAT (ares_tac prems 1));
```
```   555 qed "UnionE";
```
```   556
```
```   557 AddIs  [UnionI];
```
```   558 AddSEs [UnionE];
```
```   559
```
```   560
```
```   561 section "Inter";
```
```   562
```
```   563 Goalw [Inter_def] "(A : Inter(C)) = (ALL X:C. A:X)";
```
```   564 by (Blast_tac 1);
```
```   565 qed "Inter_iff";
```
```   566
```
```   567 Addsimps [Inter_iff];
```
```   568
```
```   569 val prems = Goalw [Inter_def]
```
```   570     "[| !!X. X:C ==> A:X |] ==> A : Inter(C)";
```
```   571 by (REPEAT (ares_tac ([INT_I] @ prems) 1));
```
```   572 qed "InterI";
```
```   573
```
```   574 (*A "destruct" rule -- every X in C contains A as an element, but
```
```   575   A:X can hold when X:C does not!  This rule is analogous to "spec". *)
```
```   576 Goal "[| A : Inter(C);  X:C |] ==> A:X";
```
```   577 by Auto_tac;
```
```   578 qed "InterD";
```
```   579
```
```   580 (*"Classical" elimination rule -- does not require proving X:C *)
```
```   581 val major::prems = Goalw [Inter_def]
```
```   582     "[| A : Inter(C);  X~:C ==> R;  A:X ==> R |] ==> R";
```
```   583 by (rtac (major RS INT_E) 1);
```
```   584 by (REPEAT (eresolve_tac prems 1));
```
```   585 qed "InterE";
```
```   586
```
```   587 AddSIs [InterI];
```
```   588 AddEs  [InterD, InterE];
```
```   589
```
```   590
```
```   591 (*** Image of a set under a function ***)
```
```   592
```
```   593 (*Frequently b does not have the syntactic form of f(x).*)
```
```   594 Goalw [image_def] "[| b=f(x);  x:A |] ==> b : f``A";
```
```   595 by (Blast_tac 1);
```
```   596 qed "image_eqI";
```
```   597 Addsimps [image_eqI];
```
```   598
```
```   599 bind_thm ("imageI", refl RS image_eqI);
```
```   600
```
```   601 (*The eta-expansion gives variable-name preservation.*)
```
```   602 val major::prems = Goalw [image_def]
```
```   603     "[| b : (%x. f(x))``A;  !!x.[| b=f(x);  x:A |] ==> P |] ==> P";
```
```   604 by (rtac (major RS CollectD RS bexE) 1);
```
```   605 by (REPEAT (ares_tac prems 1));
```
```   606 qed "imageE";
```
```   607
```
```   608 AddIs  [image_eqI];
```
```   609 AddSEs [imageE];
```
```   610
```
```   611 Goal "f``(A Un B) = f``A Un f``B";
```
```   612 by (Blast_tac 1);
```
```   613 qed "image_Un";
```
```   614
```
```   615 Goal "(z : f``A) = (EX x:A. z = f x)";
```
```   616 by (Blast_tac 1);
```
```   617 qed "image_iff";
```
```   618
```
```   619 (*This rewrite rule would confuse users if made default.*)
```
```   620 Goal "(f``A <= B) = (ALL x:A. f(x): B)";
```
```   621 by (Blast_tac 1);
```
```   622 qed "image_subset_iff";
```
```   623
```
```   624 (*Replaces the three steps subsetI, imageE, hyp_subst_tac, but breaks too
```
```   625   many existing proofs.*)
```
```   626 val prems = Goal "(!!x. x:A ==> f(x) : B) ==> f``A <= B";
```
```   627 by (blast_tac (claset() addIs prems) 1);
```
```   628 qed "image_subsetI";
```
```   629
```
```   630
```
```   631 (*** Range of a function -- just a translation for image! ***)
```
```   632
```
```   633 Goal "b=f(x) ==> b : range(f)";
```
```   634 by (EVERY1 [etac image_eqI, rtac UNIV_I]);
```
```   635 bind_thm ("range_eqI", UNIV_I RSN (2,image_eqI));
```
```   636
```
```   637 bind_thm ("rangeI", UNIV_I RS imageI);
```
```   638
```
```   639 val [major,minor] = Goal
```
```   640     "[| b : range(%x. f(x));  !!x. b=f(x) ==> P |] ==> P";
```
```   641 by (rtac (major RS imageE) 1);
```
```   642 by (etac minor 1);
```
```   643 qed "rangeE";
```
```   644
```
```   645
```
```   646 (*** Set reasoning tools ***)
```
```   647
```
```   648
```
```   649 (** Rewrite rules for boolean case-splitting: faster than
```
```   650 	addsplits[split_if]
```
```   651 **)
```
```   652
```
```   653 bind_thm ("split_if_eq1", read_instantiate [("P", "%x. x = ?b")] split_if);
```
```   654 bind_thm ("split_if_eq2", read_instantiate [("P", "%x. ?a = x")] split_if);
```
```   655
```
```   656 (*Split ifs on either side of the membership relation.
```
```   657 	Not for Addsimps -- can cause goals to blow up!*)
```
```   658 bind_thm ("split_if_mem1",
```
```   659     read_instantiate_sg (sign_of Set.thy) [("P", "%x. x : ?b")] split_if);
```
```   660 bind_thm ("split_if_mem2",
```
```   661     read_instantiate_sg (sign_of Set.thy) [("P", "%x. ?a : x")] split_if);
```
```   662
```
```   663 val split_ifs = [if_bool_eq_conj, split_if_eq1, split_if_eq2,
```
```   664 		  split_if_mem1, split_if_mem2];
```
```   665
```
```   666
```
```   667 (*Each of these has ALREADY been added to simpset() above.*)
```
```   668 val mem_simps = [insert_iff, empty_iff, Un_iff, Int_iff, Compl_iff, Diff_iff,
```
```   669                  mem_Collect_eq, UN_iff, Union_iff, INT_iff, Inter_iff];
```
```   670
```
```   671 val mksimps_pairs = ("Ball",[bspec]) :: mksimps_pairs;
```
```   672
```
```   673 simpset_ref() := simpset() setmksimps (mksimps mksimps_pairs);
```
```   674
```
```   675 Addsimps[subset_UNIV, subset_refl];
```
```   676
```
```   677
```
```   678 (*** < ***)
```
```   679
```
```   680 Goalw [psubset_def] "!!A::'a set. [| A <= B; A ~= B |] ==> A<B";
```
```   681 by (Blast_tac 1);
```
```   682 qed "psubsetI";
```
```   683
```
```   684 Goalw [psubset_def] "A < insert x B ==> (x ~: A) & A<=B | x:A & A-{x}<B";
```
```   685 by Auto_tac;
```
```   686 qed "psubset_insertD";
```
```   687
```
```   688 bind_thm ("psubset_eq", psubset_def RS meta_eq_to_obj_eq);
```