(* Title: ZF/AC/AC15_WO6.thy
ID: $Id$
Author: Krzysztof Grabczewski
The proofs needed to state that AC10, ..., AC15 are equivalent to the rest.
We need the following:
WO1 ==> AC10(n) ==> AC11 ==> AC12 ==> AC15 ==> WO6
In order to add the formulations AC13 and AC14 we need:
AC10(succ(n)) ==> AC13(n) ==> AC14 ==> AC15
or
AC1 ==> AC13(1); AC13(m) ==> AC13(n) ==> AC14 ==> AC15 (m\<le>n)
So we don't have to prove all implications of both cases.
Moreover we don't need to prove AC13(1) ==> AC1 and AC11 ==> AC14 as
Rubin & Rubin do.
*)
theory AC15_WO6 = HH + Cardinal_aux:
(* ********************************************************************** *)
(* Lemmas used in the proofs in which the conclusion is AC13, AC14 *)
(* or AC15 *)
(* - cons_times_nat_not_Finite *)
(* - ex_fun_AC13_AC15 *)
(* ********************************************************************** *)
lemma lepoll_Sigma: "A\<noteq>0 ==> B \<lesssim> A*B"
apply (unfold lepoll_def)
apply (erule not_emptyE)
apply (rule_tac x = "\<lambda>z \<in> B. <x,z>" in exI)
apply (fast intro!: snd_conv lam_injective)
done
lemma cons_times_nat_not_Finite:
"0\<notin>A ==> \<forall>B \<in> {cons(0,x*nat). x \<in> A}. ~Finite(B)"
apply clarify
apply (drule subset_consI [THEN subset_imp_lepoll, THEN lepoll_Finite])
apply (rule nat_not_Finite [THEN notE] )
apply (subgoal_tac "x ~= 0")
apply (blast intro: lepoll_Sigma [THEN lepoll_Finite], blast)
done
lemma lemma1: "[| Union(C)=A; a \<in> A |] ==> \<exists>B \<in> C. a \<in> B & B \<subseteq> A"
by fast
lemma lemma2:
"[| pairwise_disjoint(A); B \<in> A; C \<in> A; a \<in> B; a \<in> C |] ==> B=C"
by (unfold pairwise_disjoint_def, blast)
lemma lemma3:
"\<forall>B \<in> {cons(0, x*nat). x \<in> A}. pairwise_disjoint(f`B) &
sets_of_size_between(f`B, 2, n) & Union(f`B)=B
==> \<forall>B \<in> A. \<exists>! u. u \<in> f`cons(0, B*nat) & u \<subseteq> cons(0, B*nat) &
0 \<in> u & 2 \<lesssim> u & u \<lesssim> n"
apply (unfold sets_of_size_between_def)
apply (rule ballI)
apply (erule_tac x="cons(0, B*nat)" in ballE)
apply (blast dest: lemma1 intro!: lemma2, blast)
done
lemma lemma4: "[| A \<lesssim> i; Ord(i) |] ==> {P(a). a \<in> A} \<lesssim> i"
apply (unfold lepoll_def)
apply (erule exE)
apply (rule_tac x = "\<lambda>x \<in> RepFun(A,P). LEAST j. \<exists>a\<in>A. x=P(a) & f`a=j"
in exI)
apply (rule_tac d = "%y. P (converse (f) `y) " in lam_injective)
apply (erule RepFunE)
apply (frule inj_is_fun [THEN apply_type], assumption)
apply (fast intro: LeastI2 elim!: Ord_in_Ord inj_is_fun [THEN apply_type])
apply (erule RepFunE)
apply (rule LeastI2)
apply fast
apply (fast elim!: Ord_in_Ord inj_is_fun [THEN apply_type])
apply (fast elim: sym left_inverse [THEN ssubst])
done
lemma lemma5_1:
"[| B \<in> A; 2 \<lesssim> u(B) |] ==> (\<lambda>x \<in> A. {fst(x). x \<in> u(x)-{0}})`B \<noteq> 0"
apply simp
apply (fast dest: lepoll_Diff_sing
elim: lepoll_trans [THEN succ_lepoll_natE] ssubst
intro!: lepoll_refl)
done
lemma lemma5_2:
"[| B \<in> A; u(B) \<subseteq> cons(0, B*nat) |]
==> (\<lambda>x \<in> A. {fst(x). x \<in> u(x)-{0}})`B \<subseteq> B"
apply auto
done
lemma lemma5_3:
"[| n \<in> nat; B \<in> A; 0 \<in> u(B); u(B) \<lesssim> succ(n) |]
==> (\<lambda>x \<in> A. {fst(x). x \<in> u(x)-{0}})`B \<lesssim> n"
apply simp
apply (fast elim!: Diff_lepoll [THEN lemma4 [OF _ nat_into_Ord]])
done
lemma ex_fun_AC13_AC15:
"[| \<forall>B \<in> {cons(0, x*nat). x \<in> A}.
pairwise_disjoint(f`B) &
sets_of_size_between(f`B, 2, succ(n)) & Union(f`B)=B;
n \<in> nat |]
==> \<exists>f. \<forall>B \<in> A. f`B \<noteq> 0 & f`B \<subseteq> B & f`B \<lesssim> n"
by (fast del: subsetI notI
dest!: lemma3 theI intro!: lemma5_1 lemma5_2 lemma5_3)
(* ********************************************************************** *)
(* The target proofs *)
(* ********************************************************************** *)
(* ********************************************************************** *)
(* AC10(n) ==> AC11 *)
(* ********************************************************************** *)
theorem AC10_AC11: "[| n \<in> nat; 1\<le>n; AC10(n) |] ==> AC11"
by (unfold AC10_def AC11_def, blast)
(* ********************************************************************** *)
(* AC11 ==> AC12 *)
(* ********************************************************************** *)
theorem AC11_AC12: "AC11 ==> AC12"
by (unfold AC10_def AC11_def AC11_def AC12_def, blast)
(* ********************************************************************** *)
(* AC12 ==> AC15 *)
(* ********************************************************************** *)
theorem AC12_AC15: "AC12 ==> AC15"
apply (unfold AC12_def AC15_def)
apply (blast del: ballI
intro!: cons_times_nat_not_Finite ex_fun_AC13_AC15)
done
(* ********************************************************************** *)
(* AC15 ==> WO6 *)
(* ********************************************************************** *)
lemma OUN_eq_UN: "Ord(x) ==> (\<Union>a<x. F(a)) = (\<Union>a \<in> x. F(a))"
by (fast intro!: ltI dest!: ltD)
lemma lemma1:
"\<forall>x \<in> Pow(A)-{0}. f`x\<noteq>0 & f`x \<subseteq> x & f`x \<lesssim> m
==> (\<Union>i<LEAST x. HH(f,A,x)={A}. HH(f,A,i)) = A"
apply (simp add: Ord_Least [THEN OUN_eq_UN])
apply (rule equalityI)
apply (fast dest!: less_Least_subset_x)
apply (blast del: subsetI
intro!: f_subsets_imp_UN_HH_eq_x [THEN Diff_eq_0_iff [THEN iffD1]])
done
lemma lemma2:
"\<forall>x \<in> Pow(A)-{0}. f`x\<noteq>0 & f`x \<subseteq> x & f`x \<lesssim> m
==> \<forall>x < (LEAST x. HH(f,A,x)={A}). HH(f,A,x) \<lesssim> m"
apply (rule oallI)
apply (drule ltD [THEN less_Least_subset_x])
apply (frule HH_subset_imp_eq)
apply (erule ssubst)
apply (blast dest!: HH_subset_x_imp_subset_Diff_UN [THEN not_emptyI2])
(*but can't use del: DiffE despite the obvious conflictc*)
done
theorem AC15_WO6: "AC15 ==> WO6"
apply (unfold AC15_def WO6_def)
apply (rule allI)
apply (erule_tac x = "Pow (A) -{0}" in allE)
apply (erule impE, fast)
apply (elim bexE conjE exE)
apply (rule bexI)
apply (rule conjI, assumption)
apply (rule_tac x = "LEAST i. HH (f,A,i) ={A}" in exI)
apply (rule_tac x = "\<lambda>j \<in> (LEAST i. HH (f,A,i) ={A}) . HH (f,A,j) " in exI)
apply (simp_all add: ltD)
apply (fast intro!: Ord_Least lam_type [THEN domain_of_fun]
elim!: less_Least_subset_x lemma1 lemma2)
done
(* ********************************************************************** *)
(* The proof needed in the first case, not in the second *)
(* ********************************************************************** *)
(* ********************************************************************** *)
(* AC10(n) ==> AC13(n-1) if 2\<le>n *)
(* *)
(* Because of the change to the formal definition of AC10(n) we prove *)
(* the following obviously equivalent theorem \<in> *)
(* AC10(n) implies AC13(n) for (1\<le>n) *)
(* ********************************************************************** *)
theorem AC10_AC13: "[| n \<in> nat; 1\<le>n; AC10(n) |] ==> AC13(n)"
apply (unfold AC10_def AC13_def, safe)
apply (erule allE)
apply (erule impE [OF _ cons_times_nat_not_Finite], assumption)
apply (fast elim!: impE [OF _ cons_times_nat_not_Finite]
dest!: ex_fun_AC13_AC15)
done
(* ********************************************************************** *)
(* The proofs needed in the second case, not in the first *)
(* ********************************************************************** *)
(* ********************************************************************** *)
(* AC1 ==> AC13(1) *)
(* ********************************************************************** *)
lemma AC1_AC13: "AC1 ==> AC13(1)"
apply (unfold AC1_def AC13_def)
apply (rule allI)
apply (erule allE)
apply (rule impI)
apply (drule mp, assumption)
apply (elim exE)
apply (rule_tac x = "\<lambda>x \<in> A. {f`x}" in exI)
apply (simp add: singleton_eqpoll_1 [THEN eqpoll_imp_lepoll])
done
(* ********************************************************************** *)
(* AC13(m) ==> AC13(n) for m \<subseteq> n *)
(* ********************************************************************** *)
lemma AC13_mono: "[| m\<le>n; AC13(m) |] ==> AC13(n)"
apply (unfold AC13_def)
apply (drule le_imp_lepoll)
apply (fast elim!: lepoll_trans)
done
(* ********************************************************************** *)
(* The proofs necessary for both cases *)
(* ********************************************************************** *)
(* ********************************************************************** *)
(* AC13(n) ==> AC14 if 1 \<subseteq> n *)
(* ********************************************************************** *)
theorem AC13_AC14: "[| n \<in> nat; 1\<le>n; AC13(n) |] ==> AC14"
by (unfold AC13_def AC14_def, auto)
(* ********************************************************************** *)
(* AC14 ==> AC15 *)
(* ********************************************************************** *)
theorem AC14_AC15: "AC14 ==> AC15"
by (unfold AC13_def AC14_def AC15_def, fast)
(* ********************************************************************** *)
(* The redundant proofs; however cited by Rubin & Rubin *)
(* ********************************************************************** *)
(* ********************************************************************** *)
(* AC13(1) ==> AC1 *)
(* ********************************************************************** *)
lemma lemma_aux: "[| A\<noteq>0; A \<lesssim> 1 |] ==> \<exists>a. A={a}"
by (fast elim!: not_emptyE lepoll_1_is_sing)
lemma AC13_AC1_lemma:
"\<forall>B \<in> A. f(B)\<noteq>0 & f(B)<=B & f(B) \<lesssim> 1
==> (\<lambda>x \<in> A. THE y. f(x)={y}) \<in> (\<Pi>X \<in> A. X)"
apply (rule lam_type)
apply (drule bspec, assumption)
apply (elim conjE)
apply (erule lemma_aux [THEN exE], assumption)
apply (simp add: the_equality)
done
theorem AC13_AC1: "AC13(1) ==> AC1"
apply (unfold AC13_def AC1_def)
apply (fast elim!: AC13_AC1_lemma)
done
(* ********************************************************************** *)
(* AC11 ==> AC14 *)
(* ********************************************************************** *)
theorem AC11_AC14: "AC11 ==> AC14"
apply (unfold AC11_def AC14_def)
apply (fast intro!: AC10_AC13)
done
end