src/HOL/Complete_Lattice.thy
changeset 32139 e271a64f03ff
parent 32135 f645b51e8e54
child 32436 10cd49e0c067
equal deleted inserted replaced
32136:672dfd59ff03 32139:e271a64f03ff
       
     1 (*  Author:     Tobias Nipkow, Lawrence C Paulson and Markus Wenzel; Florian Haftmann, TU Muenchen *)
       
     2 
       
     3 header {* Complete lattices, with special focus on sets *}
       
     4 
       
     5 theory Complete_Lattice
       
     6 imports Set
       
     7 begin
       
     8 
       
     9 notation
       
    10   less_eq  (infix "\<sqsubseteq>" 50) and
       
    11   less (infix "\<sqsubset>" 50) and
       
    12   inf  (infixl "\<sqinter>" 70) and
       
    13   sup  (infixl "\<squnion>" 65)
       
    14 
       
    15 
       
    16 subsection {* Abstract complete lattices *}
       
    17 
       
    18 class complete_lattice = lattice + bot + top +
       
    19   fixes Inf :: "'a set \<Rightarrow> 'a" ("\<Sqinter>_" [900] 900)
       
    20     and Sup :: "'a set \<Rightarrow> 'a" ("\<Squnion>_" [900] 900)
       
    21   assumes Inf_lower: "x \<in> A \<Longrightarrow> \<Sqinter>A \<sqsubseteq> x"
       
    22      and Inf_greatest: "(\<And>x. x \<in> A \<Longrightarrow> z \<sqsubseteq> x) \<Longrightarrow> z \<sqsubseteq> \<Sqinter>A"
       
    23   assumes Sup_upper: "x \<in> A \<Longrightarrow> x \<sqsubseteq> \<Squnion>A"
       
    24      and Sup_least: "(\<And>x. x \<in> A \<Longrightarrow> x \<sqsubseteq> z) \<Longrightarrow> \<Squnion>A \<sqsubseteq> z"
       
    25 begin
       
    26 
       
    27 lemma Inf_Sup: "\<Sqinter>A = \<Squnion>{b. \<forall>a \<in> A. b \<le> a}"
       
    28   by (auto intro: antisym Inf_lower Inf_greatest Sup_upper Sup_least)
       
    29 
       
    30 lemma Sup_Inf:  "\<Squnion>A = \<Sqinter>{b. \<forall>a \<in> A. a \<le> b}"
       
    31   by (auto intro: antisym Inf_lower Inf_greatest Sup_upper Sup_least)
       
    32 
       
    33 lemma Inf_Univ: "\<Sqinter>UNIV = \<Squnion>{}"
       
    34   unfolding Sup_Inf by auto
       
    35 
       
    36 lemma Sup_Univ: "\<Squnion>UNIV = \<Sqinter>{}"
       
    37   unfolding Inf_Sup by auto
       
    38 
       
    39 lemma Inf_insert: "\<Sqinter>insert a A = a \<sqinter> \<Sqinter>A"
       
    40   by (auto intro: le_infI le_infI1 le_infI2 antisym Inf_greatest Inf_lower)
       
    41 
       
    42 lemma Sup_insert: "\<Squnion>insert a A = a \<squnion> \<Squnion>A"
       
    43   by (auto intro: le_supI le_supI1 le_supI2 antisym Sup_least Sup_upper)
       
    44 
       
    45 lemma Inf_singleton [simp]:
       
    46   "\<Sqinter>{a} = a"
       
    47   by (auto intro: antisym Inf_lower Inf_greatest)
       
    48 
       
    49 lemma Sup_singleton [simp]:
       
    50   "\<Squnion>{a} = a"
       
    51   by (auto intro: antisym Sup_upper Sup_least)
       
    52 
       
    53 lemma Inf_insert_simp:
       
    54   "\<Sqinter>insert a A = (if A = {} then a else a \<sqinter> \<Sqinter>A)"
       
    55   by (cases "A = {}") (simp_all, simp add: Inf_insert)
       
    56 
       
    57 lemma Sup_insert_simp:
       
    58   "\<Squnion>insert a A = (if A = {} then a else a \<squnion> \<Squnion>A)"
       
    59   by (cases "A = {}") (simp_all, simp add: Sup_insert)
       
    60 
       
    61 lemma Inf_binary:
       
    62   "\<Sqinter>{a, b} = a \<sqinter> b"
       
    63   by (auto simp add: Inf_insert_simp)
       
    64 
       
    65 lemma Sup_binary:
       
    66   "\<Squnion>{a, b} = a \<squnion> b"
       
    67   by (auto simp add: Sup_insert_simp)
       
    68 
       
    69 lemma bot_def:
       
    70   "bot = \<Squnion>{}"
       
    71   by (auto intro: antisym Sup_least)
       
    72 
       
    73 lemma top_def:
       
    74   "top = \<Sqinter>{}"
       
    75   by (auto intro: antisym Inf_greatest)
       
    76 
       
    77 lemma sup_bot [simp]:
       
    78   "x \<squnion> bot = x"
       
    79   using bot_least [of x] by (simp add: le_iff_sup sup_commute)
       
    80 
       
    81 lemma inf_top [simp]:
       
    82   "x \<sqinter> top = x"
       
    83   using top_greatest [of x] by (simp add: le_iff_inf inf_commute)
       
    84 
       
    85 definition SUPR :: "'b set \<Rightarrow> ('b \<Rightarrow> 'a) \<Rightarrow> 'a" where
       
    86   "SUPR A f = \<Squnion> (f ` A)"
       
    87 
       
    88 definition INFI :: "'b set \<Rightarrow> ('b \<Rightarrow> 'a) \<Rightarrow> 'a" where
       
    89   "INFI A f = \<Sqinter> (f ` A)"
       
    90 
       
    91 end
       
    92 
       
    93 syntax
       
    94   "_SUP1"     :: "pttrns => 'b => 'b"           ("(3SUP _./ _)" [0, 10] 10)
       
    95   "_SUP"      :: "pttrn => 'a set => 'b => 'b"  ("(3SUP _:_./ _)" [0, 10] 10)
       
    96   "_INF1"     :: "pttrns => 'b => 'b"           ("(3INF _./ _)" [0, 10] 10)
       
    97   "_INF"      :: "pttrn => 'a set => 'b => 'b"  ("(3INF _:_./ _)" [0, 10] 10)
       
    98 
       
    99 translations
       
   100   "SUP x y. B"   == "SUP x. SUP y. B"
       
   101   "SUP x. B"     == "CONST SUPR CONST UNIV (%x. B)"
       
   102   "SUP x. B"     == "SUP x:CONST UNIV. B"
       
   103   "SUP x:A. B"   == "CONST SUPR A (%x. B)"
       
   104   "INF x y. B"   == "INF x. INF y. B"
       
   105   "INF x. B"     == "CONST INFI CONST UNIV (%x. B)"
       
   106   "INF x. B"     == "INF x:CONST UNIV. B"
       
   107   "INF x:A. B"   == "CONST INFI A (%x. B)"
       
   108 
       
   109 print_translation {* [
       
   110 Syntax.preserve_binder_abs2_tr' @{const_syntax SUPR} "_SUP",
       
   111 Syntax.preserve_binder_abs2_tr' @{const_syntax INFI} "_INF"
       
   112 ] *} -- {* to avoid eta-contraction of body *}
       
   113 
       
   114 context complete_lattice
       
   115 begin
       
   116 
       
   117 lemma le_SUPI: "i : A \<Longrightarrow> M i \<le> (SUP i:A. M i)"
       
   118   by (auto simp add: SUPR_def intro: Sup_upper)
       
   119 
       
   120 lemma SUP_leI: "(\<And>i. i : A \<Longrightarrow> M i \<le> u) \<Longrightarrow> (SUP i:A. M i) \<le> u"
       
   121   by (auto simp add: SUPR_def intro: Sup_least)
       
   122 
       
   123 lemma INF_leI: "i : A \<Longrightarrow> (INF i:A. M i) \<le> M i"
       
   124   by (auto simp add: INFI_def intro: Inf_lower)
       
   125 
       
   126 lemma le_INFI: "(\<And>i. i : A \<Longrightarrow> u \<le> M i) \<Longrightarrow> u \<le> (INF i:A. M i)"
       
   127   by (auto simp add: INFI_def intro: Inf_greatest)
       
   128 
       
   129 lemma SUP_const[simp]: "A \<noteq> {} \<Longrightarrow> (SUP i:A. M) = M"
       
   130   by (auto intro: antisym SUP_leI le_SUPI)
       
   131 
       
   132 lemma INF_const[simp]: "A \<noteq> {} \<Longrightarrow> (INF i:A. M) = M"
       
   133   by (auto intro: antisym INF_leI le_INFI)
       
   134 
       
   135 end
       
   136 
       
   137 
       
   138 subsection {* @{typ bool} and @{typ "_ \<Rightarrow> _"} as complete lattice *}
       
   139 
       
   140 instantiation bool :: complete_lattice
       
   141 begin
       
   142 
       
   143 definition
       
   144   Inf_bool_def: "\<Sqinter>A \<longleftrightarrow> (\<forall>x\<in>A. x)"
       
   145 
       
   146 definition
       
   147   Sup_bool_def: "\<Squnion>A \<longleftrightarrow> (\<exists>x\<in>A. x)"
       
   148 
       
   149 instance proof
       
   150 qed (auto simp add: Inf_bool_def Sup_bool_def le_bool_def)
       
   151 
       
   152 end
       
   153 
       
   154 lemma Inf_empty_bool [simp]:
       
   155   "\<Sqinter>{}"
       
   156   unfolding Inf_bool_def by auto
       
   157 
       
   158 lemma not_Sup_empty_bool [simp]:
       
   159   "\<not> \<Squnion>{}"
       
   160   unfolding Sup_bool_def by auto
       
   161 
       
   162 lemma INFI_bool_eq:
       
   163   "INFI = Ball"
       
   164 proof (rule ext)+
       
   165   fix A :: "'a set"
       
   166   fix P :: "'a \<Rightarrow> bool"
       
   167   show "(INF x:A. P x) \<longleftrightarrow> (\<forall>x \<in> A. P x)"
       
   168     by (auto simp add: Ball_def INFI_def Inf_bool_def)
       
   169 qed
       
   170 
       
   171 lemma SUPR_bool_eq:
       
   172   "SUPR = Bex"
       
   173 proof (rule ext)+
       
   174   fix A :: "'a set"
       
   175   fix P :: "'a \<Rightarrow> bool"
       
   176   show "(SUP x:A. P x) \<longleftrightarrow> (\<exists>x \<in> A. P x)"
       
   177     by (auto simp add: Bex_def SUPR_def Sup_bool_def)
       
   178 qed
       
   179 
       
   180 instantiation "fun" :: (type, complete_lattice) complete_lattice
       
   181 begin
       
   182 
       
   183 definition
       
   184   Inf_fun_def [code del]: "\<Sqinter>A = (\<lambda>x. \<Sqinter>{y. \<exists>f\<in>A. y = f x})"
       
   185 
       
   186 definition
       
   187   Sup_fun_def [code del]: "\<Squnion>A = (\<lambda>x. \<Squnion>{y. \<exists>f\<in>A. y = f x})"
       
   188 
       
   189 instance proof
       
   190 qed (auto simp add: Inf_fun_def Sup_fun_def le_fun_def
       
   191   intro: Inf_lower Sup_upper Inf_greatest Sup_least)
       
   192 
       
   193 end
       
   194 
       
   195 lemma Inf_empty_fun:
       
   196   "\<Sqinter>{} = (\<lambda>_. \<Sqinter>{})"
       
   197   by (simp add: Inf_fun_def)
       
   198 
       
   199 lemma Sup_empty_fun:
       
   200   "\<Squnion>{} = (\<lambda>_. \<Squnion>{})"
       
   201   by (simp add: Sup_fun_def)
       
   202 
       
   203 
       
   204 subsection {* Union *}
       
   205 
       
   206 definition Union :: "'a set set \<Rightarrow> 'a set" where
       
   207   Sup_set_eq [symmetric]: "Union S = \<Squnion>S"
       
   208 
       
   209 notation (xsymbols)
       
   210   Union  ("\<Union>_" [90] 90)
       
   211 
       
   212 lemma Union_eq:
       
   213   "\<Union>A = {x. \<exists>B \<in> A. x \<in> B}"
       
   214 proof (rule set_ext)
       
   215   fix x
       
   216   have "(\<exists>Q\<in>{P. \<exists>B\<in>A. P \<longleftrightarrow> x \<in> B}. Q) \<longleftrightarrow> (\<exists>B\<in>A. x \<in> B)"
       
   217     by auto
       
   218   then show "x \<in> \<Union>A \<longleftrightarrow> x \<in> {x. \<exists>B\<in>A. x \<in> B}"
       
   219     by (simp add: Sup_set_eq [symmetric] Sup_fun_def Sup_bool_def) (simp add: mem_def)
       
   220 qed
       
   221 
       
   222 lemma Union_iff [simp, noatp]:
       
   223   "A \<in> \<Union>C \<longleftrightarrow> (\<exists>X\<in>C. A\<in>X)"
       
   224   by (unfold Union_eq) blast
       
   225 
       
   226 lemma UnionI [intro]:
       
   227   "X \<in> C \<Longrightarrow> A \<in> X \<Longrightarrow> A \<in> \<Union>C"
       
   228   -- {* The order of the premises presupposes that @{term C} is rigid;
       
   229     @{term A} may be flexible. *}
       
   230   by auto
       
   231 
       
   232 lemma UnionE [elim!]:
       
   233   "A \<in> \<Union>C \<Longrightarrow> (\<And>X. A\<in>X \<Longrightarrow> X\<in>C \<Longrightarrow> R) \<Longrightarrow> R"
       
   234   by auto
       
   235 
       
   236 lemma Union_upper: "B \<in> A ==> B \<subseteq> Union A"
       
   237   by (iprover intro: subsetI UnionI)
       
   238 
       
   239 lemma Union_least: "(!!X. X \<in> A ==> X \<subseteq> C) ==> Union A \<subseteq> C"
       
   240   by (iprover intro: subsetI elim: UnionE dest: subsetD)
       
   241 
       
   242 lemma Un_eq_Union: "A \<union> B = \<Union>{A, B}"
       
   243   by blast
       
   244 
       
   245 lemma Union_empty [simp]: "Union({}) = {}"
       
   246   by blast
       
   247 
       
   248 lemma Union_UNIV [simp]: "Union UNIV = UNIV"
       
   249   by blast
       
   250 
       
   251 lemma Union_insert [simp]: "Union (insert a B) = a \<union> \<Union>B"
       
   252   by blast
       
   253 
       
   254 lemma Union_Un_distrib [simp]: "\<Union>(A Un B) = \<Union>A \<union> \<Union>B"
       
   255   by blast
       
   256 
       
   257 lemma Union_Int_subset: "\<Union>(A \<inter> B) \<subseteq> \<Union>A \<inter> \<Union>B"
       
   258   by blast
       
   259 
       
   260 lemma Union_empty_conv [simp,noatp]: "(\<Union>A = {}) = (\<forall>x\<in>A. x = {})"
       
   261   by blast
       
   262 
       
   263 lemma empty_Union_conv [simp,noatp]: "({} = \<Union>A) = (\<forall>x\<in>A. x = {})"
       
   264   by blast
       
   265 
       
   266 lemma Union_disjoint: "(\<Union>C \<inter> A = {}) = (\<forall>B\<in>C. B \<inter> A = {})"
       
   267   by blast
       
   268 
       
   269 lemma subset_Pow_Union: "A \<subseteq> Pow (\<Union>A)"
       
   270   by blast
       
   271 
       
   272 lemma Union_Pow_eq [simp]: "\<Union>(Pow A) = A"
       
   273   by blast
       
   274 
       
   275 lemma Union_mono: "A \<subseteq> B ==> \<Union>A \<subseteq> \<Union>B"
       
   276   by blast
       
   277 
       
   278 
       
   279 subsection {* Unions of families *}
       
   280 
       
   281 definition UNION :: "'a set \<Rightarrow> ('a \<Rightarrow> 'b set) \<Rightarrow> 'b set" where
       
   282   SUPR_set_eq [symmetric]: "UNION S f = (SUP x:S. f x)"
       
   283 
       
   284 syntax
       
   285   "@UNION1"     :: "pttrns => 'b set => 'b set"           ("(3UN _./ _)" [0, 10] 10)
       
   286   "@UNION"      :: "pttrn => 'a set => 'b set => 'b set"  ("(3UN _:_./ _)" [0, 10] 10)
       
   287 
       
   288 syntax (xsymbols)
       
   289   "@UNION1"     :: "pttrns => 'b set => 'b set"           ("(3\<Union>_./ _)" [0, 10] 10)
       
   290   "@UNION"      :: "pttrn => 'a set => 'b set => 'b set"  ("(3\<Union>_\<in>_./ _)" [0, 10] 10)
       
   291 
       
   292 syntax (latex output)
       
   293   "@UNION1"     :: "pttrns => 'b set => 'b set"           ("(3\<Union>(00\<^bsub>_\<^esub>)/ _)" [0, 10] 10)
       
   294   "@UNION"      :: "pttrn => 'a set => 'b set => 'b set"  ("(3\<Union>(00\<^bsub>_\<in>_\<^esub>)/ _)" [0, 10] 10)
       
   295 
       
   296 translations
       
   297   "UN x y. B"   == "UN x. UN y. B"
       
   298   "UN x. B"     == "CONST UNION CONST UNIV (%x. B)"
       
   299   "UN x. B"     == "UN x:CONST UNIV. B"
       
   300   "UN x:A. B"   == "CONST UNION A (%x. B)"
       
   301 
       
   302 text {*
       
   303   Note the difference between ordinary xsymbol syntax of indexed
       
   304   unions and intersections (e.g.\ @{text"\<Union>a\<^isub>1\<in>A\<^isub>1. B"})
       
   305   and their \LaTeX\ rendition: @{term"\<Union>a\<^isub>1\<in>A\<^isub>1. B"}. The
       
   306   former does not make the index expression a subscript of the
       
   307   union/intersection symbol because this leads to problems with nested
       
   308   subscripts in Proof General.
       
   309 *}
       
   310 
       
   311 print_translation {* [
       
   312 Syntax.preserve_binder_abs2_tr' @{const_syntax UNION} "@UNION"
       
   313 ] *} -- {* to avoid eta-contraction of body *}
       
   314 
       
   315 lemma UNION_eq_Union_image:
       
   316   "(\<Union>x\<in>A. B x) = \<Union>(B`A)"
       
   317   by (simp add: SUPR_def SUPR_set_eq [symmetric] Sup_set_eq)
       
   318 
       
   319 lemma Union_def:
       
   320   "\<Union>S = (\<Union>x\<in>S. x)"
       
   321   by (simp add: UNION_eq_Union_image image_def)
       
   322 
       
   323 lemma UNION_def [noatp]:
       
   324   "(\<Union>x\<in>A. B x) = {y. \<exists>x\<in>A. y \<in> B x}"
       
   325   by (auto simp add: UNION_eq_Union_image Union_eq)
       
   326   
       
   327 lemma Union_image_eq [simp]:
       
   328   "\<Union>(B`A) = (\<Union>x\<in>A. B x)"
       
   329   by (rule sym) (fact UNION_eq_Union_image)
       
   330   
       
   331 lemma UN_iff [simp]: "(b: (UN x:A. B x)) = (EX x:A. b: B x)"
       
   332   by (unfold UNION_def) blast
       
   333 
       
   334 lemma UN_I [intro]: "a:A ==> b: B a ==> b: (UN x:A. B x)"
       
   335   -- {* The order of the premises presupposes that @{term A} is rigid;
       
   336     @{term b} may be flexible. *}
       
   337   by auto
       
   338 
       
   339 lemma UN_E [elim!]: "b : (UN x:A. B x) ==> (!!x. x:A ==> b: B x ==> R) ==> R"
       
   340   by (unfold UNION_def) blast
       
   341 
       
   342 lemma UN_cong [cong]:
       
   343     "A = B ==> (!!x. x:B ==> C x = D x) ==> (UN x:A. C x) = (UN x:B. D x)"
       
   344   by (simp add: UNION_def)
       
   345 
       
   346 lemma strong_UN_cong:
       
   347     "A = B ==> (!!x. x:B =simp=> C x = D x) ==> (UN x:A. C x) = (UN x:B. D x)"
       
   348   by (simp add: UNION_def simp_implies_def)
       
   349 
       
   350 lemma image_eq_UN: "f`A = (UN x:A. {f x})"
       
   351   by blast
       
   352 
       
   353 lemma UN_upper: "a \<in> A ==> B a \<subseteq> (\<Union>x\<in>A. B x)"
       
   354   by blast
       
   355 
       
   356 lemma UN_least: "(!!x. x \<in> A ==> B x \<subseteq> C) ==> (\<Union>x\<in>A. B x) \<subseteq> C"
       
   357   by (iprover intro: subsetI elim: UN_E dest: subsetD)
       
   358 
       
   359 lemma Collect_bex_eq [noatp]: "{x. \<exists>y\<in>A. P x y} = (\<Union>y\<in>A. {x. P x y})"
       
   360   by blast
       
   361 
       
   362 lemma UN_insert_distrib: "u \<in> A ==> (\<Union>x\<in>A. insert a (B x)) = insert a (\<Union>x\<in>A. B x)"
       
   363   by blast
       
   364 
       
   365 lemma UN_empty [simp,noatp]: "(\<Union>x\<in>{}. B x) = {}"
       
   366   by blast
       
   367 
       
   368 lemma UN_empty2 [simp]: "(\<Union>x\<in>A. {}) = {}"
       
   369   by blast
       
   370 
       
   371 lemma UN_singleton [simp]: "(\<Union>x\<in>A. {x}) = A"
       
   372   by blast
       
   373 
       
   374 lemma UN_absorb: "k \<in> I ==> A k \<union> (\<Union>i\<in>I. A i) = (\<Union>i\<in>I. A i)"
       
   375   by auto
       
   376 
       
   377 lemma UN_insert [simp]: "(\<Union>x\<in>insert a A. B x) = B a \<union> UNION A B"
       
   378   by blast
       
   379 
       
   380 lemma UN_Un[simp]: "(\<Union>i \<in> A \<union> B. M i) = (\<Union>i\<in>A. M i) \<union> (\<Union>i\<in>B. M i)"
       
   381   by blast
       
   382 
       
   383 lemma UN_UN_flatten: "(\<Union>x \<in> (\<Union>y\<in>A. B y). C x) = (\<Union>y\<in>A. \<Union>x\<in>B y. C x)"
       
   384   by blast
       
   385 
       
   386 lemma UN_subset_iff: "((\<Union>i\<in>I. A i) \<subseteq> B) = (\<forall>i\<in>I. A i \<subseteq> B)"
       
   387   by blast
       
   388 
       
   389 lemma image_Union: "f ` \<Union>S = (\<Union>x\<in>S. f ` x)"
       
   390   by blast
       
   391 
       
   392 lemma UN_constant [simp]: "(\<Union>y\<in>A. c) = (if A = {} then {} else c)"
       
   393   by auto
       
   394 
       
   395 lemma UN_eq: "(\<Union>x\<in>A. B x) = \<Union>({Y. \<exists>x\<in>A. Y = B x})"
       
   396   by blast
       
   397 
       
   398 lemma UNION_empty_conv[simp]:
       
   399   "({} = (UN x:A. B x)) = (\<forall>x\<in>A. B x = {})"
       
   400   "((UN x:A. B x) = {}) = (\<forall>x\<in>A. B x = {})"
       
   401 by blast+
       
   402 
       
   403 lemma Collect_ex_eq [noatp]: "{x. \<exists>y. P x y} = (\<Union>y. {x. P x y})"
       
   404   by blast
       
   405 
       
   406 lemma ball_UN: "(\<forall>z \<in> UNION A B. P z) = (\<forall>x\<in>A. \<forall>z \<in> B x. P z)"
       
   407   by blast
       
   408 
       
   409 lemma bex_UN: "(\<exists>z \<in> UNION A B. P z) = (\<exists>x\<in>A. \<exists>z\<in>B x. P z)"
       
   410   by blast
       
   411 
       
   412 lemma Un_eq_UN: "A \<union> B = (\<Union>b. if b then A else B)"
       
   413   by (auto simp add: split_if_mem2)
       
   414 
       
   415 lemma UN_bool_eq: "(\<Union>b::bool. A b) = (A True \<union> A False)"
       
   416   by (auto intro: bool_contrapos)
       
   417 
       
   418 lemma UN_Pow_subset: "(\<Union>x\<in>A. Pow (B x)) \<subseteq> Pow (\<Union>x\<in>A. B x)"
       
   419   by blast
       
   420 
       
   421 lemma UN_mono:
       
   422   "A \<subseteq> B ==> (!!x. x \<in> A ==> f x \<subseteq> g x) ==>
       
   423     (\<Union>x\<in>A. f x) \<subseteq> (\<Union>x\<in>B. g x)"
       
   424   by (blast dest: subsetD)
       
   425 
       
   426 lemma vimage_Union: "f -` (Union A) = (UN X:A. f -` X)"
       
   427   by blast
       
   428 
       
   429 lemma vimage_UN: "f-`(UN x:A. B x) = (UN x:A. f -` B x)"
       
   430   by blast
       
   431 
       
   432 lemma vimage_eq_UN: "f-`B = (UN y: B. f-`{y})"
       
   433   -- {* NOT suitable for rewriting *}
       
   434   by blast
       
   435 
       
   436 lemma image_UN: "(f ` (UNION A B)) = (UN x:A.(f ` (B x)))"
       
   437 by blast
       
   438 
       
   439 
       
   440 subsection {* Inter *}
       
   441 
       
   442 definition Inter :: "'a set set \<Rightarrow> 'a set" where
       
   443   Inf_set_eq [symmetric]: "Inter S = \<Sqinter>S"
       
   444   
       
   445 notation (xsymbols)
       
   446   Inter  ("\<Inter>_" [90] 90)
       
   447 
       
   448 lemma Inter_eq [code del]:
       
   449   "\<Inter>A = {x. \<forall>B \<in> A. x \<in> B}"
       
   450 proof (rule set_ext)
       
   451   fix x
       
   452   have "(\<forall>Q\<in>{P. \<exists>B\<in>A. P \<longleftrightarrow> x \<in> B}. Q) \<longleftrightarrow> (\<forall>B\<in>A. x \<in> B)"
       
   453     by auto
       
   454   then show "x \<in> \<Inter>A \<longleftrightarrow> x \<in> {x. \<forall>B \<in> A. x \<in> B}"
       
   455     by (simp add: Inf_fun_def Inf_bool_def Inf_set_eq [symmetric]) (simp add: mem_def)
       
   456 qed
       
   457 
       
   458 lemma Inter_iff [simp,noatp]: "(A : Inter C) = (ALL X:C. A:X)"
       
   459   by (unfold Inter_eq) blast
       
   460 
       
   461 lemma InterI [intro!]: "(!!X. X:C ==> A:X) ==> A : Inter C"
       
   462   by (simp add: Inter_eq)
       
   463 
       
   464 text {*
       
   465   \medskip A ``destruct'' rule -- every @{term X} in @{term C}
       
   466   contains @{term A} as an element, but @{prop "A:X"} can hold when
       
   467   @{prop "X:C"} does not!  This rule is analogous to @{text spec}.
       
   468 *}
       
   469 
       
   470 lemma InterD [elim]: "A : Inter C ==> X:C ==> A:X"
       
   471   by auto
       
   472 
       
   473 lemma InterE [elim]: "A : Inter C ==> (X~:C ==> R) ==> (A:X ==> R) ==> R"
       
   474   -- {* ``Classical'' elimination rule -- does not require proving
       
   475     @{prop "X:C"}. *}
       
   476   by (unfold Inter_eq) blast
       
   477 
       
   478 lemma Inter_lower: "B \<in> A ==> Inter A \<subseteq> B"
       
   479   by blast
       
   480 
       
   481 lemma Inter_subset:
       
   482   "[| !!X. X \<in> A ==> X \<subseteq> B; A ~= {} |] ==> \<Inter>A \<subseteq> B"
       
   483   by blast
       
   484 
       
   485 lemma Inter_greatest: "(!!X. X \<in> A ==> C \<subseteq> X) ==> C \<subseteq> Inter A"
       
   486   by (iprover intro: InterI subsetI dest: subsetD)
       
   487 
       
   488 lemma Int_eq_Inter: "A \<inter> B = \<Inter>{A, B}"
       
   489   by blast
       
   490 
       
   491 lemma Inter_empty [simp]: "\<Inter>{} = UNIV"
       
   492   by blast
       
   493 
       
   494 lemma Inter_UNIV [simp]: "\<Inter>UNIV = {}"
       
   495   by blast
       
   496 
       
   497 lemma Inter_insert [simp]: "\<Inter>(insert a B) = a \<inter> \<Inter>B"
       
   498   by blast
       
   499 
       
   500 lemma Inter_Un_subset: "\<Inter>A \<union> \<Inter>B \<subseteq> \<Inter>(A \<inter> B)"
       
   501   by blast
       
   502 
       
   503 lemma Inter_Un_distrib: "\<Inter>(A \<union> B) = \<Inter>A \<inter> \<Inter>B"
       
   504   by blast
       
   505 
       
   506 lemma Inter_UNIV_conv [simp,noatp]:
       
   507   "(\<Inter>A = UNIV) = (\<forall>x\<in>A. x = UNIV)"
       
   508   "(UNIV = \<Inter>A) = (\<forall>x\<in>A. x = UNIV)"
       
   509   by blast+
       
   510 
       
   511 lemma Inter_anti_mono: "B \<subseteq> A ==> \<Inter>A \<subseteq> \<Inter>B"
       
   512   by blast
       
   513 
       
   514 
       
   515 subsection {* Intersections of families *}
       
   516 
       
   517 definition INTER :: "'a set \<Rightarrow> ('a \<Rightarrow> 'b set) \<Rightarrow> 'b set" where
       
   518   INFI_set_eq [symmetric]: "INTER S f = (INF x:S. f x)"
       
   519 
       
   520 syntax
       
   521   "@INTER1"     :: "pttrns => 'b set => 'b set"           ("(3INT _./ _)" [0, 10] 10)
       
   522   "@INTER"      :: "pttrn => 'a set => 'b set => 'b set"  ("(3INT _:_./ _)" [0, 10] 10)
       
   523 
       
   524 syntax (xsymbols)
       
   525   "@INTER1"     :: "pttrns => 'b set => 'b set"           ("(3\<Inter>_./ _)" [0, 10] 10)
       
   526   "@INTER"      :: "pttrn => 'a set => 'b set => 'b set"  ("(3\<Inter>_\<in>_./ _)" [0, 10] 10)
       
   527 
       
   528 syntax (latex output)
       
   529   "@INTER1"     :: "pttrns => 'b set => 'b set"           ("(3\<Inter>(00\<^bsub>_\<^esub>)/ _)" [0, 10] 10)
       
   530   "@INTER"      :: "pttrn => 'a set => 'b set => 'b set"  ("(3\<Inter>(00\<^bsub>_\<in>_\<^esub>)/ _)" [0, 10] 10)
       
   531 
       
   532 translations
       
   533   "INT x y. B"  == "INT x. INT y. B"
       
   534   "INT x. B"    == "CONST INTER CONST UNIV (%x. B)"
       
   535   "INT x. B"    == "INT x:CONST UNIV. B"
       
   536   "INT x:A. B"  == "CONST INTER A (%x. B)"
       
   537 
       
   538 print_translation {* [
       
   539 Syntax.preserve_binder_abs2_tr' @{const_syntax INTER} "@INTER"
       
   540 ] *} -- {* to avoid eta-contraction of body *}
       
   541 
       
   542 lemma INTER_eq_Inter_image:
       
   543   "(\<Inter>x\<in>A. B x) = \<Inter>(B`A)"
       
   544   by (simp add: INFI_def INFI_set_eq [symmetric] Inf_set_eq)
       
   545   
       
   546 lemma Inter_def:
       
   547   "\<Inter>S = (\<Inter>x\<in>S. x)"
       
   548   by (simp add: INTER_eq_Inter_image image_def)
       
   549 
       
   550 lemma INTER_def:
       
   551   "(\<Inter>x\<in>A. B x) = {y. \<forall>x\<in>A. y \<in> B x}"
       
   552   by (auto simp add: INTER_eq_Inter_image Inter_eq)
       
   553 
       
   554 lemma Inter_image_eq [simp]:
       
   555   "\<Inter>(B`A) = (\<Inter>x\<in>A. B x)"
       
   556   by (rule sym) (fact INTER_eq_Inter_image)
       
   557 
       
   558 lemma INT_iff [simp]: "(b: (INT x:A. B x)) = (ALL x:A. b: B x)"
       
   559   by (unfold INTER_def) blast
       
   560 
       
   561 lemma INT_I [intro!]: "(!!x. x:A ==> b: B x) ==> b : (INT x:A. B x)"
       
   562   by (unfold INTER_def) blast
       
   563 
       
   564 lemma INT_D [elim]: "b : (INT x:A. B x) ==> a:A ==> b: B a"
       
   565   by auto
       
   566 
       
   567 lemma INT_E [elim]: "b : (INT x:A. B x) ==> (b: B a ==> R) ==> (a~:A ==> R) ==> R"
       
   568   -- {* "Classical" elimination -- by the Excluded Middle on @{prop "a:A"}. *}
       
   569   by (unfold INTER_def) blast
       
   570 
       
   571 lemma INT_cong [cong]:
       
   572     "A = B ==> (!!x. x:B ==> C x = D x) ==> (INT x:A. C x) = (INT x:B. D x)"
       
   573   by (simp add: INTER_def)
       
   574 
       
   575 lemma Collect_ball_eq: "{x. \<forall>y\<in>A. P x y} = (\<Inter>y\<in>A. {x. P x y})"
       
   576   by blast
       
   577 
       
   578 lemma Collect_all_eq: "{x. \<forall>y. P x y} = (\<Inter>y. {x. P x y})"
       
   579   by blast
       
   580 
       
   581 lemma INT_lower: "a \<in> A ==> (\<Inter>x\<in>A. B x) \<subseteq> B a"
       
   582   by blast
       
   583 
       
   584 lemma INT_greatest: "(!!x. x \<in> A ==> C \<subseteq> B x) ==> C \<subseteq> (\<Inter>x\<in>A. B x)"
       
   585   by (iprover intro: INT_I subsetI dest: subsetD)
       
   586 
       
   587 lemma INT_empty [simp]: "(\<Inter>x\<in>{}. B x) = UNIV"
       
   588   by blast
       
   589 
       
   590 lemma INT_absorb: "k \<in> I ==> A k \<inter> (\<Inter>i\<in>I. A i) = (\<Inter>i\<in>I. A i)"
       
   591   by blast
       
   592 
       
   593 lemma INT_subset_iff: "(B \<subseteq> (\<Inter>i\<in>I. A i)) = (\<forall>i\<in>I. B \<subseteq> A i)"
       
   594   by blast
       
   595 
       
   596 lemma INT_insert [simp]: "(\<Inter>x \<in> insert a A. B x) = B a \<inter> INTER A B"
       
   597   by blast
       
   598 
       
   599 lemma INT_Un: "(\<Inter>i \<in> A \<union> B. M i) = (\<Inter>i \<in> A. M i) \<inter> (\<Inter>i\<in>B. M i)"
       
   600   by blast
       
   601 
       
   602 lemma INT_insert_distrib:
       
   603     "u \<in> A ==> (\<Inter>x\<in>A. insert a (B x)) = insert a (\<Inter>x\<in>A. B x)"
       
   604   by blast
       
   605 
       
   606 lemma INT_constant [simp]: "(\<Inter>y\<in>A. c) = (if A = {} then UNIV else c)"
       
   607   by auto
       
   608 
       
   609 lemma INT_eq: "(\<Inter>x\<in>A. B x) = \<Inter>({Y. \<exists>x\<in>A. Y = B x})"
       
   610   -- {* Look: it has an \emph{existential} quantifier *}
       
   611   by blast
       
   612 
       
   613 lemma INTER_UNIV_conv[simp]:
       
   614  "(UNIV = (INT x:A. B x)) = (\<forall>x\<in>A. B x = UNIV)"
       
   615  "((INT x:A. B x) = UNIV) = (\<forall>x\<in>A. B x = UNIV)"
       
   616 by blast+
       
   617 
       
   618 lemma INT_bool_eq: "(\<Inter>b::bool. A b) = (A True \<inter> A False)"
       
   619   by (auto intro: bool_induct)
       
   620 
       
   621 lemma Pow_INT_eq: "Pow (\<Inter>x\<in>A. B x) = (\<Inter>x\<in>A. Pow (B x))"
       
   622   by blast
       
   623 
       
   624 lemma INT_anti_mono:
       
   625   "B \<subseteq> A ==> (!!x. x \<in> A ==> f x \<subseteq> g x) ==>
       
   626     (\<Inter>x\<in>A. f x) \<subseteq> (\<Inter>x\<in>A. g x)"
       
   627   -- {* The last inclusion is POSITIVE! *}
       
   628   by (blast dest: subsetD)
       
   629 
       
   630 lemma vimage_INT: "f-`(INT x:A. B x) = (INT x:A. f -` B x)"
       
   631   by blast
       
   632 
       
   633 
       
   634 subsection {* Distributive laws *}
       
   635 
       
   636 lemma Int_Union: "A \<inter> \<Union>B = (\<Union>C\<in>B. A \<inter> C)"
       
   637   by blast
       
   638 
       
   639 lemma Int_Union2: "\<Union>B \<inter> A = (\<Union>C\<in>B. C \<inter> A)"
       
   640   by blast
       
   641 
       
   642 lemma Un_Union_image: "(\<Union>x\<in>C. A x \<union> B x) = \<Union>(A`C) \<union> \<Union>(B`C)"
       
   643   -- {* Devlin, Fundamentals of Contemporary Set Theory, page 12, exercise 5: *}
       
   644   -- {* Union of a family of unions *}
       
   645   by blast
       
   646 
       
   647 lemma UN_Un_distrib: "(\<Union>i\<in>I. A i \<union> B i) = (\<Union>i\<in>I. A i) \<union> (\<Union>i\<in>I. B i)"
       
   648   -- {* Equivalent version *}
       
   649   by blast
       
   650 
       
   651 lemma Un_Inter: "A \<union> \<Inter>B = (\<Inter>C\<in>B. A \<union> C)"
       
   652   by blast
       
   653 
       
   654 lemma Int_Inter_image: "(\<Inter>x\<in>C. A x \<inter> B x) = \<Inter>(A`C) \<inter> \<Inter>(B`C)"
       
   655   by blast
       
   656 
       
   657 lemma INT_Int_distrib: "(\<Inter>i\<in>I. A i \<inter> B i) = (\<Inter>i\<in>I. A i) \<inter> (\<Inter>i\<in>I. B i)"
       
   658   -- {* Equivalent version *}
       
   659   by blast
       
   660 
       
   661 lemma Int_UN_distrib: "B \<inter> (\<Union>i\<in>I. A i) = (\<Union>i\<in>I. B \<inter> A i)"
       
   662   -- {* Halmos, Naive Set Theory, page 35. *}
       
   663   by blast
       
   664 
       
   665 lemma Un_INT_distrib: "B \<union> (\<Inter>i\<in>I. A i) = (\<Inter>i\<in>I. B \<union> A i)"
       
   666   by blast
       
   667 
       
   668 lemma Int_UN_distrib2: "(\<Union>i\<in>I. A i) \<inter> (\<Union>j\<in>J. B j) = (\<Union>i\<in>I. \<Union>j\<in>J. A i \<inter> B j)"
       
   669   by blast
       
   670 
       
   671 lemma Un_INT_distrib2: "(\<Inter>i\<in>I. A i) \<union> (\<Inter>j\<in>J. B j) = (\<Inter>i\<in>I. \<Inter>j\<in>J. A i \<union> B j)"
       
   672   by blast
       
   673 
       
   674 
       
   675 subsection {* Complement *}
       
   676 
       
   677 lemma Compl_UN [simp]: "-(\<Union>x\<in>A. B x) = (\<Inter>x\<in>A. -B x)"
       
   678   by blast
       
   679 
       
   680 lemma Compl_INT [simp]: "-(\<Inter>x\<in>A. B x) = (\<Union>x\<in>A. -B x)"
       
   681   by blast
       
   682 
       
   683 
       
   684 subsection {* Miniscoping and maxiscoping *}
       
   685 
       
   686 text {* \medskip Miniscoping: pushing in quantifiers and big Unions
       
   687            and Intersections. *}
       
   688 
       
   689 lemma UN_simps [simp]:
       
   690   "!!a B C. (UN x:C. insert a (B x)) = (if C={} then {} else insert a (UN x:C. B x))"
       
   691   "!!A B C. (UN x:C. A x Un B)   = ((if C={} then {} else (UN x:C. A x) Un B))"
       
   692   "!!A B C. (UN x:C. A Un B x)   = ((if C={} then {} else A Un (UN x:C. B x)))"
       
   693   "!!A B C. (UN x:C. A x Int B)  = ((UN x:C. A x) Int B)"
       
   694   "!!A B C. (UN x:C. A Int B x)  = (A Int (UN x:C. B x))"
       
   695   "!!A B C. (UN x:C. A x - B)    = ((UN x:C. A x) - B)"
       
   696   "!!A B C. (UN x:C. A - B x)    = (A - (INT x:C. B x))"
       
   697   "!!A B. (UN x: Union A. B x) = (UN y:A. UN x:y. B x)"
       
   698   "!!A B C. (UN z: UNION A B. C z) = (UN  x:A. UN z: B(x). C z)"
       
   699   "!!A B f. (UN x:f`A. B x)     = (UN a:A. B (f a))"
       
   700   by auto
       
   701 
       
   702 lemma INT_simps [simp]:
       
   703   "!!A B C. (INT x:C. A x Int B) = (if C={} then UNIV else (INT x:C. A x) Int B)"
       
   704   "!!A B C. (INT x:C. A Int B x) = (if C={} then UNIV else A Int (INT x:C. B x))"
       
   705   "!!A B C. (INT x:C. A x - B)   = (if C={} then UNIV else (INT x:C. A x) - B)"
       
   706   "!!A B C. (INT x:C. A - B x)   = (if C={} then UNIV else A - (UN x:C. B x))"
       
   707   "!!a B C. (INT x:C. insert a (B x)) = insert a (INT x:C. B x)"
       
   708   "!!A B C. (INT x:C. A x Un B)  = ((INT x:C. A x) Un B)"
       
   709   "!!A B C. (INT x:C. A Un B x)  = (A Un (INT x:C. B x))"
       
   710   "!!A B. (INT x: Union A. B x) = (INT y:A. INT x:y. B x)"
       
   711   "!!A B C. (INT z: UNION A B. C z) = (INT x:A. INT z: B(x). C z)"
       
   712   "!!A B f. (INT x:f`A. B x)    = (INT a:A. B (f a))"
       
   713   by auto
       
   714 
       
   715 lemma ball_simps [simp,noatp]:
       
   716   "!!A P Q. (ALL x:A. P x | Q) = ((ALL x:A. P x) | Q)"
       
   717   "!!A P Q. (ALL x:A. P | Q x) = (P | (ALL x:A. Q x))"
       
   718   "!!A P Q. (ALL x:A. P --> Q x) = (P --> (ALL x:A. Q x))"
       
   719   "!!A P Q. (ALL x:A. P x --> Q) = ((EX x:A. P x) --> Q)"
       
   720   "!!P. (ALL x:{}. P x) = True"
       
   721   "!!P. (ALL x:UNIV. P x) = (ALL x. P x)"
       
   722   "!!a B P. (ALL x:insert a B. P x) = (P a & (ALL x:B. P x))"
       
   723   "!!A P. (ALL x:Union A. P x) = (ALL y:A. ALL x:y. P x)"
       
   724   "!!A B P. (ALL x: UNION A B. P x) = (ALL a:A. ALL x: B a. P x)"
       
   725   "!!P Q. (ALL x:Collect Q. P x) = (ALL x. Q x --> P x)"
       
   726   "!!A P f. (ALL x:f`A. P x) = (ALL x:A. P (f x))"
       
   727   "!!A P. (~(ALL x:A. P x)) = (EX x:A. ~P x)"
       
   728   by auto
       
   729 
       
   730 lemma bex_simps [simp,noatp]:
       
   731   "!!A P Q. (EX x:A. P x & Q) = ((EX x:A. P x) & Q)"
       
   732   "!!A P Q. (EX x:A. P & Q x) = (P & (EX x:A. Q x))"
       
   733   "!!P. (EX x:{}. P x) = False"
       
   734   "!!P. (EX x:UNIV. P x) = (EX x. P x)"
       
   735   "!!a B P. (EX x:insert a B. P x) = (P(a) | (EX x:B. P x))"
       
   736   "!!A P. (EX x:Union A. P x) = (EX y:A. EX x:y. P x)"
       
   737   "!!A B P. (EX x: UNION A B. P x) = (EX a:A. EX x:B a. P x)"
       
   738   "!!P Q. (EX x:Collect Q. P x) = (EX x. Q x & P x)"
       
   739   "!!A P f. (EX x:f`A. P x) = (EX x:A. P (f x))"
       
   740   "!!A P. (~(EX x:A. P x)) = (ALL x:A. ~P x)"
       
   741   by auto
       
   742 
       
   743 lemma ball_conj_distrib:
       
   744   "(ALL x:A. P x & Q x) = ((ALL x:A. P x) & (ALL x:A. Q x))"
       
   745   by blast
       
   746 
       
   747 lemma bex_disj_distrib:
       
   748   "(EX x:A. P x | Q x) = ((EX x:A. P x) | (EX x:A. Q x))"
       
   749   by blast
       
   750 
       
   751 
       
   752 text {* \medskip Maxiscoping: pulling out big Unions and Intersections. *}
       
   753 
       
   754 lemma UN_extend_simps:
       
   755   "!!a B C. insert a (UN x:C. B x) = (if C={} then {a} else (UN x:C. insert a (B x)))"
       
   756   "!!A B C. (UN x:C. A x) Un B    = (if C={} then B else (UN x:C. A x Un B))"
       
   757   "!!A B C. A Un (UN x:C. B x)   = (if C={} then A else (UN x:C. A Un B x))"
       
   758   "!!A B C. ((UN x:C. A x) Int B) = (UN x:C. A x Int B)"
       
   759   "!!A B C. (A Int (UN x:C. B x)) = (UN x:C. A Int B x)"
       
   760   "!!A B C. ((UN x:C. A x) - B) = (UN x:C. A x - B)"
       
   761   "!!A B C. (A - (INT x:C. B x)) = (UN x:C. A - B x)"
       
   762   "!!A B. (UN y:A. UN x:y. B x) = (UN x: Union A. B x)"
       
   763   "!!A B C. (UN  x:A. UN z: B(x). C z) = (UN z: UNION A B. C z)"
       
   764   "!!A B f. (UN a:A. B (f a)) = (UN x:f`A. B x)"
       
   765   by auto
       
   766 
       
   767 lemma INT_extend_simps:
       
   768   "!!A B C. (INT x:C. A x) Int B = (if C={} then B else (INT x:C. A x Int B))"
       
   769   "!!A B C. A Int (INT x:C. B x) = (if C={} then A else (INT x:C. A Int B x))"
       
   770   "!!A B C. (INT x:C. A x) - B   = (if C={} then UNIV-B else (INT x:C. A x - B))"
       
   771   "!!A B C. A - (UN x:C. B x)   = (if C={} then A else (INT x:C. A - B x))"
       
   772   "!!a B C. insert a (INT x:C. B x) = (INT x:C. insert a (B x))"
       
   773   "!!A B C. ((INT x:C. A x) Un B)  = (INT x:C. A x Un B)"
       
   774   "!!A B C. A Un (INT x:C. B x)  = (INT x:C. A Un B x)"
       
   775   "!!A B. (INT y:A. INT x:y. B x) = (INT x: Union A. B x)"
       
   776   "!!A B C. (INT x:A. INT z: B(x). C z) = (INT z: UNION A B. C z)"
       
   777   "!!A B f. (INT a:A. B (f a))    = (INT x:f`A. B x)"
       
   778   by auto
       
   779 
       
   780 
       
   781 no_notation
       
   782   less_eq  (infix "\<sqsubseteq>" 50) and
       
   783   less (infix "\<sqsubset>" 50) and
       
   784   inf  (infixl "\<sqinter>" 70) and
       
   785   sup  (infixl "\<squnion>" 65) and
       
   786   Inf  ("\<Sqinter>_" [900] 900) and
       
   787   Sup  ("\<Squnion>_" [900] 900)
       
   788 
       
   789 lemmas mem_simps =
       
   790   insert_iff empty_iff Un_iff Int_iff Compl_iff Diff_iff
       
   791   mem_Collect_eq UN_iff Union_iff INT_iff Inter_iff
       
   792   -- {* Each of these has ALREADY been added @{text "[simp]"} above. *}
       
   793 
       
   794 end