Theory AllocBase

theory AllocBase
imports Follows Guar
(*  Title:      ZF/UNITY/AllocBase.thy
    Author:     Sidi O Ehmety, Cambridge University Computer Laboratory
    Copyright   2001  University of Cambridge

section‹Common declarations for Chandy and Charpentier's Allocator›

theory AllocBase imports Follows MultisetSum Guar begin

abbreviation (input)
  tokbag   :: i  (* tokbags could be multisets...or any ordered type?*)
  "tokbag == nat"

  NbT :: i and  (* Number of tokens in system *)
  Nclients :: i  (* Number of clients *)
  NbT_pos: "NbT ∈ nat-{0}" and
  Nclients_pos: "Nclients ∈ nat-{0}"
text‹This function merely sums the elements of a list›
consts tokens :: "i =>i"
       item :: i (* Items to be merged/distributed *)
  "tokens(Nil) = 0"
  "tokens (Cons(x,xs)) = x #+ tokens(xs)"

consts bag_of :: "i => i"
  "bag_of(Nil)    = 0"
  "bag_of(Cons(x,xs)) = {#x#} +# bag_of(xs)"

text‹Definitions needed in Client.thy.  We define a recursive predicate
using 0 and 1 to code the truth values.›
consts all_distinct0 :: "i=>i"
  "all_distinct0(Nil) = 1"
  "all_distinct0(Cons(a, l)) =
     (if a ∈ set_of_list(l) then 0 else all_distinct0(l))"

  all_distinct  :: "i=>o"  where
   "all_distinct(l) == all_distinct0(l)=1"
  state_of :: "i =>i" ‹coersion from anyting to state›  where
   "state_of(s) == if s ∈ state then s else st0"

  lift :: "i =>(i=>i)" ‹simplifies the expression of programs›  where
   "lift(x) == %s. s`x"

text‹function to show that the set of variables is infinite›
  nat_list_inj :: "i=>i"
  var_inj      :: "i=>i"

  "nat_list_inj(0) = Nil"
  "nat_list_inj(succ(n)) = Cons(n, nat_list_inj(n))"

  "var_inj(Var(l)) = length(l)"

  nat_var_inj  :: "i=>i"  where
  "nat_var_inj(n) == Var(nat_list_inj(n))"

subsection‹Various simple lemmas›

lemma Nclients_NbT_gt_0 [simp]: "0 < Nclients & 0 < NbT"
apply (cut_tac Nclients_pos NbT_pos)
apply (auto intro: Ord_0_lt)

lemma Nclients_NbT_not_0 [simp]: "Nclients ≠ 0 & NbT ≠ 0"
by (cut_tac Nclients_pos NbT_pos, auto)

lemma Nclients_type [simp,TC]: "Nclients∈nat"
by (cut_tac Nclients_pos NbT_pos, auto)

lemma NbT_type [simp,TC]: "NbT∈nat"
by (cut_tac Nclients_pos NbT_pos, auto)

lemma INT_Nclient_iff [iff]:
     "b∈⋂(RepFun(Nclients, B)) ⟷ (∀x∈Nclients. b∈B(x))"
by (force simp add: INT_iff)

lemma setsum_fun_mono [rule_format]:
     "n∈nat ==>  
      (∀i∈nat. i<n ⟶ f(i) $≤ g(i)) ⟶  
      setsum(f, n) $≤ setsum(g,n)"
apply (induct_tac "n", simp_all)
apply (subgoal_tac "Finite(x) & x∉x")
 prefer 2 apply (simp add: nat_into_Finite mem_not_refl, clarify)
apply (simp (no_asm_simp) add: succ_def)
apply (subgoal_tac "∀i∈nat. i<x⟶ f(i) $≤ g(i) ")
 prefer 2 apply (force dest: leI) 
apply (rule zadd_zle_mono, simp_all)

lemma tokens_type [simp,TC]: "l∈list(A) ==> tokens(l)∈nat"
by (erule list.induct, auto)

lemma tokens_mono_aux [rule_format]:
     "xs∈list(A) ==> ∀ys∈list(A). <xs, ys>∈prefix(A)  
   ⟶ tokens(xs) ≤ tokens(ys)"
apply (induct_tac "xs")
apply (auto dest: gen_prefix.dom_subset [THEN subsetD] simp add: prefix_def)

lemma tokens_mono: "<xs, ys>∈prefix(A) ==> tokens(xs) ≤ tokens(ys)"
apply (cut_tac prefix_type)
apply (blast intro: tokens_mono_aux)

lemma mono_tokens [iff]: "mono1(list(A), prefix(A), nat, Le,tokens)"
apply (unfold mono1_def)
apply (auto intro: tokens_mono simp add: Le_def)

lemma tokens_append [simp]: 
"[| xs∈list(A); ys∈list(A) |] ==> tokens(xs@ys) = tokens(xs) #+ tokens(ys)"
apply (induct_tac "xs", auto)

subsection‹The function @{term bag_of}›

lemma bag_of_type [simp,TC]: "l∈list(A) ==>bag_of(l)∈Mult(A)"
apply (induct_tac "l")
apply (auto simp add: Mult_iff_multiset)

lemma bag_of_multiset:
     "l∈list(A) ==> multiset(bag_of(l)) & mset_of(bag_of(l))<=A"
apply (drule bag_of_type)
apply (auto simp add: Mult_iff_multiset)

lemma bag_of_append [simp]:
    "[| xs∈list(A); ys∈list(A)|] ==> bag_of(xs@ys) = bag_of(xs) +# bag_of(ys)"
apply (induct_tac "xs")
apply (auto simp add: bag_of_multiset munion_assoc)

lemma bag_of_mono_aux [rule_format]:
     "xs∈list(A) ==> ∀ys∈list(A). <xs, ys>∈prefix(A)  
      ⟶ <bag_of(xs), bag_of(ys)>∈MultLe(A, r)"
apply (induct_tac "xs", simp_all, clarify) 
apply (frule_tac l = ys in bag_of_multiset)
apply (auto intro: empty_le_MultLe simp add: prefix_def)
apply (rule munion_mono)
apply (force simp add: MultLe_def Mult_iff_multiset)
apply (blast dest: gen_prefix.dom_subset [THEN subsetD])

lemma bag_of_mono [intro]:
     "[|  <xs, ys>∈prefix(A); xs∈list(A); ys∈list(A) |]
      ==> <bag_of(xs), bag_of(ys)>∈MultLe(A, r)"
apply (blast intro: bag_of_mono_aux)

lemma mono_bag_of [simp]: 
     "mono1(list(A), prefix(A), Mult(A), MultLe(A,r), bag_of)"
by (auto simp add:  mono1_def bag_of_type)

subsection‹The function @{term msetsum}›

lemmas nat_into_Fin = eqpoll_refl [THEN [2] Fin_lemma]

lemma list_Int_length_Fin: "l ∈ list(A) ==> C ∩ length(l) ∈ Fin(length(l))"
apply (drule length_type)
apply (rule Fin_subset)
apply (rule Int_lower2)
apply (erule nat_into_Fin)

lemma mem_Int_imp_lt_length:
     "[|xs ∈ list(A); k ∈ C ∩ length(xs)|] ==> k < length(xs)"
by (simp add: ltI)

lemma Int_succ_right:
     "A ∩ succ(k) = (if k ∈ A then cons(k, A ∩ k) else A ∩ k)"
by auto

lemma bag_of_sublist_lemma:
     "[|C ⊆ nat; x ∈ A; xs ∈ list(A)|]   
  ==>  msetsum(λi. {#nth(i, xs @ [x])#}, C ∩ succ(length(xs)), A) =  
       (if length(xs) ∈ C then  
          {#x#} +# msetsum(λx. {#nth(x, xs)#}, C ∩ length(xs), A)  
        else msetsum(λx. {#nth(x, xs)#}, C ∩ length(xs), A))"
apply (simp add: subsetD nth_append lt_not_refl mem_Int_imp_lt_length cong add: msetsum_cong)
apply (simp add: Int_succ_right)
apply (simp add: lt_not_refl mem_Int_imp_lt_length cong add: msetsum_cong, clarify)
apply (subst msetsum_cons)
apply (rule_tac [3] succI1)
apply (blast intro: list_Int_length_Fin subset_succI [THEN Fin_mono, THEN subsetD])
apply (simp add: mem_not_refl)
apply (simp add: nth_type lt_not_refl)
apply (blast intro: nat_into_Ord ltI length_type)
apply (simp add: lt_not_refl mem_Int_imp_lt_length cong add: msetsum_cong)

lemma bag_of_sublist_lemma2:
     "l∈list(A) ==>  
  C ⊆ nat ==>  
  bag_of(sublist(l, C)) =  
      msetsum(%i. {#nth(i, l)#}, C ∩ length(l), A)"
apply (erule list_append_induct)
apply (simp (no_asm))
apply (simp (no_asm_simp) add: sublist_append nth_append bag_of_sublist_lemma munion_commute bag_of_sublist_lemma msetsum_multiset munion_0)

lemma nat_Int_length_eq: "l ∈ list(A) ==> nat ∩ length(l) = length(l)"
apply (rule Int_absorb1)
apply (rule OrdmemD, auto)

(*eliminating the assumption C<=nat*)
lemma bag_of_sublist:
     "l∈list(A) ==>  
  bag_of(sublist(l, C)) = msetsum(%i. {#nth(i, l)#}, C ∩ length(l), A)"
apply (subgoal_tac " bag_of (sublist (l, C ∩ nat)) = msetsum (%i. {#nth (i, l) #}, C ∩ length (l), A) ")
apply (simp add: sublist_Int_eq)
apply (simp add: bag_of_sublist_lemma2 Int_lower2 Int_assoc nat_Int_length_eq)

lemma bag_of_sublist_Un_Int: 
"l∈list(A) ==>  
  bag_of(sublist(l, B ∪ C)) +# bag_of(sublist(l, B ∩ C)) =  
      bag_of(sublist(l, B)) +# bag_of(sublist(l, C))"
apply (subgoal_tac "B ∩ C ∩ length (l) = (B ∩ length (l)) ∩ (C ∩ length (l))")
prefer 2 apply blast
apply (simp (no_asm_simp) add: bag_of_sublist Int_Un_distrib2 msetsum_Un_Int)
apply (rule msetsum_Un_Int)
apply (erule list_Int_length_Fin)+
 apply (simp add: ltI nth_type)

lemma bag_of_sublist_Un_disjoint:
     "[| l∈list(A); B ∩ C = 0  |] 
      ==> bag_of(sublist(l, B ∪ C)) =  
          bag_of(sublist(l, B)) +# bag_of(sublist(l, C))"
by (simp add: bag_of_sublist_Un_Int [symmetric] bag_of_multiset)

lemma bag_of_sublist_UN_disjoint [rule_format]:
     "[|Finite(I); ∀i∈I. ∀j∈I. i≠j ⟶ A(i) ∩ A(j) = 0;  
        l∈list(B) |]  
      ==> bag_of(sublist(l, ⋃i∈I. A(i))) =   
          (msetsum(%i. bag_of(sublist(l, A(i))), I, B)) "
apply (simp (no_asm_simp) del: UN_simps
           add: UN_simps [symmetric] bag_of_sublist)
apply (subst  msetsum_UN_disjoint [of _ _ _ "length (l)"])
apply (drule Finite_into_Fin, assumption)
prefer 3 apply force
apply (auto intro!: Fin_IntI2 Finite_into_Fin simp add: ltI nth_type length_type nat_into_Finite)

lemma part_ord_Lt [simp]: "part_ord(nat, Lt)"
apply (unfold part_ord_def Lt_def irrefl_def trans_on_def)
apply (auto intro: lt_trans)

subsubsection‹The function @{term all_distinct}›

lemma all_distinct_Nil [simp]: "all_distinct(Nil)"
by (unfold all_distinct_def, auto)

lemma all_distinct_Cons [simp]: 
    "all_distinct(Cons(a,l)) ⟷  
      (a∈set_of_list(l) ⟶ False) & (a ∉ set_of_list(l) ⟶ all_distinct(l))"
apply (unfold all_distinct_def)
apply (auto elim: list.cases)

subsubsection‹The function @{term state_of}›

lemma state_of_state: "s∈state ==> state_of(s)=s"
by (unfold state_of_def, auto)
declare state_of_state [simp]

lemma state_of_idem: "state_of(state_of(s))=state_of(s)"

apply (unfold state_of_def, auto)
declare state_of_idem [simp]

lemma state_of_type [simp,TC]: "state_of(s)∈state"
by (unfold state_of_def, auto)

lemma lift_apply [simp]: "lift(x, s)=s`x"
by (simp add: lift_def)

(** Used in ClientImp **)

lemma gen_Increains_state_of_eq: 
     "Increasing(A, r, %s. f(state_of(s))) = Increasing(A, r, f)"
apply (unfold Increasing_def, auto)

lemmas Increasing_state_ofD1 =  
      gen_Increains_state_of_eq [THEN equalityD1, THEN subsetD]
lemmas Increasing_state_ofD2 =  
      gen_Increains_state_of_eq [THEN equalityD2, THEN subsetD]

lemma Follows_state_of_eq: 
     "Follows(A, r, %s. f(state_of(s)), %s. g(state_of(s))) =   
      Follows(A, r, f, g)"
apply (unfold Follows_def Increasing_def, auto)

lemmas Follows_state_ofD1 =
      Follows_state_of_eq [THEN equalityD1, THEN subsetD]
lemmas Follows_state_ofD2 =
      Follows_state_of_eq [THEN equalityD2, THEN subsetD]

lemma nat_list_inj_type: "n∈nat ==> nat_list_inj(n)∈list(nat)"
by (induct_tac "n", auto)

lemma length_nat_list_inj: "n∈nat ==> length(nat_list_inj(n)) = n"
by (induct_tac "n", auto)

lemma var_infinite_lemma: 
  "(λx∈nat. nat_var_inj(x))∈inj(nat, var)"
apply (unfold nat_var_inj_def)
apply (rule_tac d = var_inj in lam_injective)
apply (auto simp add: var.intros nat_list_inj_type)
apply (simp add: length_nat_list_inj)

lemma nat_lepoll_var: "nat ≲ var"
apply (unfold lepoll_def)
apply (rule_tac x = " (λx∈nat. nat_var_inj (x))" in exI)
apply (rule var_infinite_lemma)

lemma var_not_Finite: "~Finite(var)"
apply (insert nat_not_Finite) 
apply (blast intro: lepoll_Finite [OF nat_lepoll_var]) 

lemma not_Finite_imp_exist: "~Finite(A) ==> ∃x. x∈A"
apply (subgoal_tac "A≠0")
apply (auto simp add: Finite_0)

lemma Inter_Diff_var_iff:
     "Finite(A) ==> b∈(⋂(RepFun(var-A, B))) ⟷ (∀x∈var-A. b∈B(x))"
apply (subgoal_tac "∃x. x∈var-A", auto)
apply (subgoal_tac "~Finite (var-A) ")
apply (drule not_Finite_imp_exist, auto)
apply (cut_tac var_not_Finite)
apply (erule swap)
apply (rule_tac B = A in Diff_Finite, auto)

lemma Inter_var_DiffD:
     "[| b∈⋂(RepFun(var-A, B)); Finite(A); x∈var-A |] ==> b∈B(x)"
by (simp add: Inter_Diff_var_iff)

(* [| Finite(A); (∀x∈var-A. b∈B(x)) |] ==> b∈⋂(RepFun(var-A, B)) *)
lemmas Inter_var_DiffI = Inter_Diff_var_iff [THEN iffD2]

declare Inter_var_DiffI [intro!]

lemma Acts_subset_Int_Pow_simp [simp]:
     "Acts(F)<= A ∩ Pow(state*state)  ⟷ Acts(F)<=A"
by (insert Acts_type [of F], auto)

lemma setsum_nsetsum_eq: 
     "[| Finite(A); ∀x∈A. g(x)∈nat |] 
      ==> setsum(%x. $#(g(x)), A) = $# nsetsum(%x. g(x), A)"
apply (erule Finite_induct)
apply (auto simp add: int_of_add)

lemma nsetsum_cong: 
     "[| A=B;  ∀x∈A. f(x)=g(x);  ∀x∈A. g(x)∈nat;  Finite(A) |]  
      ==> nsetsum(f, A) = nsetsum(g, B)"
apply (subgoal_tac "$# nsetsum (f, A) = $# nsetsum (g, B)", simp)
apply (simp add: setsum_nsetsum_eq [symmetric] cong: setsum_cong)