src/HOL/Lattices.thy
changeset 30302 5ffa9d4dbea7
parent 29580 117b88da143c
child 30729 461ee3e49ad3
equal deleted inserted replaced
30301:429612400fe9 30302:5ffa9d4dbea7
     3 *)
     3 *)
     4 
     4 
     5 header {* Abstract lattices *}
     5 header {* Abstract lattices *}
     6 
     6 
     7 theory Lattices
     7 theory Lattices
     8 imports Fun
     8 imports Orderings
     9 begin
     9 begin
    10 
    10 
    11 subsection {* Lattices *}
    11 subsection {* Lattices *}
    12 
    12 
    13 notation
    13 notation
   326 lemmas [rule del] = min_max.le_infI min_max.le_supI
   326 lemmas [rule del] = min_max.le_infI min_max.le_supI
   327   min_max.le_supE min_max.le_infE min_max.le_supI1 min_max.le_supI2
   327   min_max.le_supE min_max.le_infE min_max.le_supI1 min_max.le_supI2
   328   min_max.le_infI1 min_max.le_infI2
   328   min_max.le_infI1 min_max.le_infI2
   329 
   329 
   330 
   330 
   331 subsection {* Complete lattices *}
       
   332 
       
   333 class complete_lattice = lattice + bot + top +
       
   334   fixes Inf :: "'a set \<Rightarrow> 'a" ("\<Sqinter>_" [900] 900)
       
   335     and Sup :: "'a set \<Rightarrow> 'a" ("\<Squnion>_" [900] 900)
       
   336   assumes Inf_lower: "x \<in> A \<Longrightarrow> \<Sqinter>A \<sqsubseteq> x"
       
   337      and Inf_greatest: "(\<And>x. x \<in> A \<Longrightarrow> z \<sqsubseteq> x) \<Longrightarrow> z \<sqsubseteq> \<Sqinter>A"
       
   338   assumes Sup_upper: "x \<in> A \<Longrightarrow> x \<sqsubseteq> \<Squnion>A"
       
   339      and Sup_least: "(\<And>x. x \<in> A \<Longrightarrow> x \<sqsubseteq> z) \<Longrightarrow> \<Squnion>A \<sqsubseteq> z"
       
   340 begin
       
   341 
       
   342 lemma Inf_Sup: "\<Sqinter>A = \<Squnion>{b. \<forall>a \<in> A. b \<le> a}"
       
   343   by (auto intro: antisym Inf_lower Inf_greatest Sup_upper Sup_least)
       
   344 
       
   345 lemma Sup_Inf:  "\<Squnion>A = \<Sqinter>{b. \<forall>a \<in> A. a \<le> b}"
       
   346   by (auto intro: antisym Inf_lower Inf_greatest Sup_upper Sup_least)
       
   347 
       
   348 lemma Inf_Univ: "\<Sqinter>UNIV = \<Squnion>{}"
       
   349   unfolding Sup_Inf by auto
       
   350 
       
   351 lemma Sup_Univ: "\<Squnion>UNIV = \<Sqinter>{}"
       
   352   unfolding Inf_Sup by auto
       
   353 
       
   354 lemma Inf_insert: "\<Sqinter>insert a A = a \<sqinter> \<Sqinter>A"
       
   355   by (auto intro: antisym Inf_greatest Inf_lower)
       
   356 
       
   357 lemma Sup_insert: "\<Squnion>insert a A = a \<squnion> \<Squnion>A"
       
   358   by (auto intro: antisym Sup_least Sup_upper)
       
   359 
       
   360 lemma Inf_singleton [simp]:
       
   361   "\<Sqinter>{a} = a"
       
   362   by (auto intro: antisym Inf_lower Inf_greatest)
       
   363 
       
   364 lemma Sup_singleton [simp]:
       
   365   "\<Squnion>{a} = a"
       
   366   by (auto intro: antisym Sup_upper Sup_least)
       
   367 
       
   368 lemma Inf_insert_simp:
       
   369   "\<Sqinter>insert a A = (if A = {} then a else a \<sqinter> \<Sqinter>A)"
       
   370   by (cases "A = {}") (simp_all, simp add: Inf_insert)
       
   371 
       
   372 lemma Sup_insert_simp:
       
   373   "\<Squnion>insert a A = (if A = {} then a else a \<squnion> \<Squnion>A)"
       
   374   by (cases "A = {}") (simp_all, simp add: Sup_insert)
       
   375 
       
   376 lemma Inf_binary:
       
   377   "\<Sqinter>{a, b} = a \<sqinter> b"
       
   378   by (simp add: Inf_insert_simp)
       
   379 
       
   380 lemma Sup_binary:
       
   381   "\<Squnion>{a, b} = a \<squnion> b"
       
   382   by (simp add: Sup_insert_simp)
       
   383 
       
   384 lemma bot_def:
       
   385   "bot = \<Squnion>{}"
       
   386   by (auto intro: antisym Sup_least)
       
   387 
       
   388 lemma top_def:
       
   389   "top = \<Sqinter>{}"
       
   390   by (auto intro: antisym Inf_greatest)
       
   391 
       
   392 lemma sup_bot [simp]:
       
   393   "x \<squnion> bot = x"
       
   394   using bot_least [of x] by (simp add: le_iff_sup sup_commute)
       
   395 
       
   396 lemma inf_top [simp]:
       
   397   "x \<sqinter> top = x"
       
   398   using top_greatest [of x] by (simp add: le_iff_inf inf_commute)
       
   399 
       
   400 definition SUPR :: "'b set \<Rightarrow> ('b \<Rightarrow> 'a) \<Rightarrow> 'a" where
       
   401   "SUPR A f == \<Squnion> (f ` A)"
       
   402 
       
   403 definition INFI :: "'b set \<Rightarrow> ('b \<Rightarrow> 'a) \<Rightarrow> 'a" where
       
   404   "INFI A f == \<Sqinter> (f ` A)"
       
   405 
       
   406 end
       
   407 
       
   408 syntax
       
   409   "_SUP1"     :: "pttrns => 'b => 'b"           ("(3SUP _./ _)" [0, 10] 10)
       
   410   "_SUP"      :: "pttrn => 'a set => 'b => 'b"  ("(3SUP _:_./ _)" [0, 10] 10)
       
   411   "_INF1"     :: "pttrns => 'b => 'b"           ("(3INF _./ _)" [0, 10] 10)
       
   412   "_INF"      :: "pttrn => 'a set => 'b => 'b"  ("(3INF _:_./ _)" [0, 10] 10)
       
   413 
       
   414 translations
       
   415   "SUP x y. B"   == "SUP x. SUP y. B"
       
   416   "SUP x. B"     == "CONST SUPR UNIV (%x. B)"
       
   417   "SUP x. B"     == "SUP x:UNIV. B"
       
   418   "SUP x:A. B"   == "CONST SUPR A (%x. B)"
       
   419   "INF x y. B"   == "INF x. INF y. B"
       
   420   "INF x. B"     == "CONST INFI UNIV (%x. B)"
       
   421   "INF x. B"     == "INF x:UNIV. B"
       
   422   "INF x:A. B"   == "CONST INFI A (%x. B)"
       
   423 
       
   424 (* To avoid eta-contraction of body: *)
       
   425 print_translation {*
       
   426 let
       
   427   fun btr' syn (A :: Abs abs :: ts) =
       
   428     let val (x,t) = atomic_abs_tr' abs
       
   429     in list_comb (Syntax.const syn $ x $ A $ t, ts) end
       
   430   val const_syntax_name = Sign.const_syntax_name @{theory} o fst o dest_Const
       
   431 in
       
   432 [(const_syntax_name @{term SUPR}, btr' "_SUP"),(const_syntax_name @{term "INFI"}, btr' "_INF")]
       
   433 end
       
   434 *}
       
   435 
       
   436 context complete_lattice
       
   437 begin
       
   438 
       
   439 lemma le_SUPI: "i : A \<Longrightarrow> M i \<le> (SUP i:A. M i)"
       
   440   by (auto simp add: SUPR_def intro: Sup_upper)
       
   441 
       
   442 lemma SUP_leI: "(\<And>i. i : A \<Longrightarrow> M i \<le> u) \<Longrightarrow> (SUP i:A. M i) \<le> u"
       
   443   by (auto simp add: SUPR_def intro: Sup_least)
       
   444 
       
   445 lemma INF_leI: "i : A \<Longrightarrow> (INF i:A. M i) \<le> M i"
       
   446   by (auto simp add: INFI_def intro: Inf_lower)
       
   447 
       
   448 lemma le_INFI: "(\<And>i. i : A \<Longrightarrow> u \<le> M i) \<Longrightarrow> u \<le> (INF i:A. M i)"
       
   449   by (auto simp add: INFI_def intro: Inf_greatest)
       
   450 
       
   451 lemma SUP_const[simp]: "A \<noteq> {} \<Longrightarrow> (SUP i:A. M) = M"
       
   452   by (auto intro: antisym SUP_leI le_SUPI)
       
   453 
       
   454 lemma INF_const[simp]: "A \<noteq> {} \<Longrightarrow> (INF i:A. M) = M"
       
   455   by (auto intro: antisym INF_leI le_INFI)
       
   456 
       
   457 end
       
   458 
       
   459 
       
   460 subsection {* Bool as lattice *}
   331 subsection {* Bool as lattice *}
   461 
   332 
   462 instantiation bool :: distrib_lattice
   333 instantiation bool :: distrib_lattice
   463 begin
   334 begin
   464 
   335 
   470 
   341 
   471 instance
   342 instance
   472   by intro_classes (auto simp add: inf_bool_eq sup_bool_eq le_bool_def)
   343   by intro_classes (auto simp add: inf_bool_eq sup_bool_eq le_bool_def)
   473 
   344 
   474 end
   345 end
   475 
       
   476 instantiation bool :: complete_lattice
       
   477 begin
       
   478 
       
   479 definition
       
   480   Inf_bool_def: "\<Sqinter>A \<longleftrightarrow> (\<forall>x\<in>A. x)"
       
   481 
       
   482 definition
       
   483   Sup_bool_def: "\<Squnion>A \<longleftrightarrow> (\<exists>x\<in>A. x)"
       
   484 
       
   485 instance
       
   486   by intro_classes (auto simp add: Inf_bool_def Sup_bool_def le_bool_def)
       
   487 
       
   488 end
       
   489 
       
   490 lemma Inf_empty_bool [simp]:
       
   491   "\<Sqinter>{}"
       
   492   unfolding Inf_bool_def by auto
       
   493 
       
   494 lemma not_Sup_empty_bool [simp]:
       
   495   "\<not> Sup {}"
       
   496   unfolding Sup_bool_def by auto
       
   497 
   346 
   498 
   347 
   499 subsection {* Fun as lattice *}
   348 subsection {* Fun as lattice *}
   500 
   349 
   501 instantiation "fun" :: (type, lattice) lattice
   350 instantiation "fun" :: (type, lattice) lattice
   520 end
   369 end
   521 
   370 
   522 instance "fun" :: (type, distrib_lattice) distrib_lattice
   371 instance "fun" :: (type, distrib_lattice) distrib_lattice
   523   by default (auto simp add: inf_fun_eq sup_fun_eq sup_inf_distrib1)
   372   by default (auto simp add: inf_fun_eq sup_fun_eq sup_inf_distrib1)
   524 
   373 
   525 instantiation "fun" :: (type, complete_lattice) complete_lattice
       
   526 begin
       
   527 
       
   528 definition
       
   529   Inf_fun_def [code del]: "\<Sqinter>A = (\<lambda>x. \<Sqinter>{y. \<exists>f\<in>A. y = f x})"
       
   530 
       
   531 definition
       
   532   Sup_fun_def [code del]: "\<Squnion>A = (\<lambda>x. \<Squnion>{y. \<exists>f\<in>A. y = f x})"
       
   533 
       
   534 instance
       
   535   by intro_classes
       
   536     (auto simp add: Inf_fun_def Sup_fun_def le_fun_def
       
   537       intro: Inf_lower Sup_upper Inf_greatest Sup_least)
       
   538 
       
   539 end
       
   540 
       
   541 lemma Inf_empty_fun:
       
   542   "\<Sqinter>{} = (\<lambda>_. \<Sqinter>{})"
       
   543   by rule (auto simp add: Inf_fun_def)
       
   544 
       
   545 lemma Sup_empty_fun:
       
   546   "\<Squnion>{} = (\<lambda>_. \<Squnion>{})"
       
   547   by rule (auto simp add: Sup_fun_def)
       
   548 
       
   549 
       
   550 subsection {* Set as lattice *}
       
   551 
       
   552 lemma inf_set_eq: "A \<sqinter> B = A \<inter> B"
       
   553   apply (rule subset_antisym)
       
   554   apply (rule Int_greatest)
       
   555   apply (rule inf_le1)
       
   556   apply (rule inf_le2)
       
   557   apply (rule inf_greatest)
       
   558   apply (rule Int_lower1)
       
   559   apply (rule Int_lower2)
       
   560   done
       
   561 
       
   562 lemma sup_set_eq: "A \<squnion> B = A \<union> B"
       
   563   apply (rule subset_antisym)
       
   564   apply (rule sup_least)
       
   565   apply (rule Un_upper1)
       
   566   apply (rule Un_upper2)
       
   567   apply (rule Un_least)
       
   568   apply (rule sup_ge1)
       
   569   apply (rule sup_ge2)
       
   570   done
       
   571 
       
   572 lemma mono_Int: "mono f \<Longrightarrow> f (A \<inter> B) \<subseteq> f A \<inter> f B"
       
   573   apply (fold inf_set_eq sup_set_eq)
       
   574   apply (erule mono_inf)
       
   575   done
       
   576 
       
   577 lemma mono_Un: "mono f \<Longrightarrow> f A \<union> f B \<subseteq> f (A \<union> B)"
       
   578   apply (fold inf_set_eq sup_set_eq)
       
   579   apply (erule mono_sup)
       
   580   done
       
   581 
       
   582 lemma Inf_set_eq: "\<Sqinter>S = \<Inter>S"
       
   583   apply (rule subset_antisym)
       
   584   apply (rule Inter_greatest)
       
   585   apply (erule Inf_lower)
       
   586   apply (rule Inf_greatest)
       
   587   apply (erule Inter_lower)
       
   588   done
       
   589 
       
   590 lemma Sup_set_eq: "\<Squnion>S = \<Union>S"
       
   591   apply (rule subset_antisym)
       
   592   apply (rule Sup_least)
       
   593   apply (erule Union_upper)
       
   594   apply (rule Union_least)
       
   595   apply (erule Sup_upper)
       
   596   done
       
   597   
       
   598 lemma top_set_eq: "top = UNIV"
       
   599   by (iprover intro!: subset_antisym subset_UNIV top_greatest)
       
   600 
       
   601 lemma bot_set_eq: "bot = {}"
       
   602   by (iprover intro!: subset_antisym empty_subsetI bot_least)
       
   603 
       
   604 
   374 
   605 text {* redundant bindings *}
   375 text {* redundant bindings *}
   606 
   376 
   607 lemmas inf_aci = inf_ACI
   377 lemmas inf_aci = inf_ACI
   608 lemmas sup_aci = sup_ACI
   378 lemmas sup_aci = sup_ACI
   609 
   379 
   610 no_notation
   380 no_notation
   611   less_eq  (infix "\<sqsubseteq>" 50) and
   381   less_eq  (infix "\<sqsubseteq>" 50) and
   612   less (infix "\<sqsubset>" 50) and
   382   less (infix "\<sqsubset>" 50) and
   613   inf  (infixl "\<sqinter>" 70) and
   383   inf  (infixl "\<sqinter>" 70) and
   614   sup  (infixl "\<squnion>" 65) and
   384   sup  (infixl "\<squnion>" 65)
   615   Inf  ("\<Sqinter>_" [900] 900) and
   385 
   616   Sup  ("\<Squnion>_" [900] 900)
   386 end
   617 
       
   618 end