1 (* Title: ZF/Ordinal.thy
3 Author: Lawrence C Paulson, Cambridge University Computer Laboratory
4 Copyright 1994 University of Cambridge
8 header{*Transitive Sets and Ordinals*}
10 theory Ordinal = WF + Bool + equalities:
15 "Memrel(A) == {z: A*A . EX x y. z=<x,y> & x:y }"
18 "Transset(i) == ALL x:i. x<=i"
21 "Ord(i) == Transset(i) & (ALL x:i. Transset(x))"
23 lt :: "[i,i] => o" (infixl "<" 50) (*less-than on ordinals*)
27 "Limit(i) == Ord(i) & 0<i & (ALL y. y<i --> succ(y)<i)"
30 "le" :: "[i,i] => o" (infixl 50) (*less-than or equals*)
33 "x le y" == "x < succ(y)"
36 "op le" :: "[i,i] => o" (infixl "\<le>" 50) (*less-than or equals*)
39 subsection{*Rules for Transset*}
41 subsubsection{*Three Neat Characterisations of Transset*}
43 lemma Transset_iff_Pow: "Transset(A) <-> A<=Pow(A)"
44 by (unfold Transset_def, blast)
46 lemma Transset_iff_Union_succ: "Transset(A) <-> Union(succ(A)) = A"
47 apply (unfold Transset_def)
48 apply (blast elim!: equalityE)
51 lemma Transset_iff_Union_subset: "Transset(A) <-> Union(A) <= A"
52 by (unfold Transset_def, blast)
54 subsubsection{*Consequences of Downwards Closure*}
56 lemma Transset_doubleton_D:
57 "[| Transset(C); {a,b}: C |] ==> a:C & b: C"
58 by (unfold Transset_def, blast)
60 lemma Transset_Pair_D:
61 "[| Transset(C); <a,b>: C |] ==> a:C & b: C"
62 apply (simp add: Pair_def)
63 apply (blast dest: Transset_doubleton_D)
66 lemma Transset_includes_domain:
67 "[| Transset(C); A*B <= C; b: B |] ==> A <= C"
68 by (blast dest: Transset_Pair_D)
70 lemma Transset_includes_range:
71 "[| Transset(C); A*B <= C; a: A |] ==> B <= C"
72 by (blast dest: Transset_Pair_D)
74 subsubsection{*Closure Properties*}
76 lemma Transset_0: "Transset(0)"
77 by (unfold Transset_def, blast)
80 "[| Transset(i); Transset(j) |] ==> Transset(i Un j)"
81 by (unfold Transset_def, blast)
84 "[| Transset(i); Transset(j) |] ==> Transset(i Int j)"
85 by (unfold Transset_def, blast)
87 lemma Transset_succ: "Transset(i) ==> Transset(succ(i))"
88 by (unfold Transset_def, blast)
90 lemma Transset_Pow: "Transset(i) ==> Transset(Pow(i))"
91 by (unfold Transset_def, blast)
93 lemma Transset_Union: "Transset(A) ==> Transset(Union(A))"
94 by (unfold Transset_def, blast)
96 lemma Transset_Union_family:
97 "[| !!i. i:A ==> Transset(i) |] ==> Transset(Union(A))"
98 by (unfold Transset_def, blast)
100 lemma Transset_Inter_family:
101 "[| !!i. i:A ==> Transset(i) |] ==> Transset(Inter(A))"
102 by (unfold Inter_def Transset_def, blast)
105 "(!!x. x \<in> A ==> Transset(B(x))) ==> Transset (\<Union>x\<in>A. B(x))"
106 by (rule Transset_Union_family, auto)
109 "(!!x. x \<in> A ==> Transset(B(x))) ==> Transset (\<Inter>x\<in>A. B(x))"
110 by (rule Transset_Inter_family, auto)
113 subsection{*Lemmas for Ordinals*}
116 "[| Transset(i); !!x. x:i ==> Transset(x) |] ==> Ord(i)"
117 by (simp add: Ord_def)
119 lemma Ord_is_Transset: "Ord(i) ==> Transset(i)"
120 by (simp add: Ord_def)
122 lemma Ord_contains_Transset:
123 "[| Ord(i); j:i |] ==> Transset(j) "
124 by (unfold Ord_def, blast)
127 lemma Ord_in_Ord: "[| Ord(i); j:i |] ==> Ord(j)"
128 by (unfold Ord_def Transset_def, blast)
130 (*suitable for rewriting PROVIDED i has been fixed*)
131 lemma Ord_in_Ord': "[| j:i; Ord(i) |] ==> Ord(j)"
132 by (blast intro: Ord_in_Ord)
134 (* Ord(succ(j)) ==> Ord(j) *)
135 lemmas Ord_succD = Ord_in_Ord [OF _ succI1]
137 lemma Ord_subset_Ord: "[| Ord(i); Transset(j); j<=i |] ==> Ord(j)"
138 by (simp add: Ord_def Transset_def, blast)
140 lemma OrdmemD: "[| j:i; Ord(i) |] ==> j<=i"
141 by (unfold Ord_def Transset_def, blast)
143 lemma Ord_trans: "[| i:j; j:k; Ord(k) |] ==> i:k"
144 by (blast dest: OrdmemD)
146 lemma Ord_succ_subsetI: "[| i:j; Ord(j) |] ==> succ(i) <= j"
147 by (blast dest: OrdmemD)
150 subsection{*The Construction of Ordinals: 0, succ, Union*}
152 lemma Ord_0 [iff,TC]: "Ord(0)"
153 by (blast intro: OrdI Transset_0)
155 lemma Ord_succ [TC]: "Ord(i) ==> Ord(succ(i))"
156 by (blast intro: OrdI Transset_succ Ord_is_Transset Ord_contains_Transset)
158 lemmas Ord_1 = Ord_0 [THEN Ord_succ]
160 lemma Ord_succ_iff [iff]: "Ord(succ(i)) <-> Ord(i)"
161 by (blast intro: Ord_succ dest!: Ord_succD)
163 lemma Ord_Un [intro,simp,TC]: "[| Ord(i); Ord(j) |] ==> Ord(i Un j)"
164 apply (unfold Ord_def)
165 apply (blast intro!: Transset_Un)
168 lemma Ord_Int [TC]: "[| Ord(i); Ord(j) |] ==> Ord(i Int j)"
169 apply (unfold Ord_def)
170 apply (blast intro!: Transset_Int)
173 (*There is no set of all ordinals, for then it would contain itself*)
174 lemma ON_class: "~ (ALL i. i:X <-> Ord(i))"
176 apply (frule_tac x = X in spec)
177 apply (safe elim!: mem_irrefl)
178 apply (erule swap, rule OrdI [OF _ Ord_is_Transset])
179 apply (simp add: Transset_def)
180 apply (blast intro: Ord_in_Ord)+
183 subsection{*< is 'less Than' for Ordinals*}
185 lemma ltI: "[| i:j; Ord(j) |] ==> i<j"
186 by (unfold lt_def, blast)
189 "[| i<j; [| i:j; Ord(i); Ord(j) |] ==> P |] ==> P"
190 apply (unfold lt_def)
191 apply (blast intro: Ord_in_Ord)
194 lemma ltD: "i<j ==> i:j"
195 by (erule ltE, assumption)
197 lemma not_lt0 [simp]: "~ i<0"
198 by (unfold lt_def, blast)
200 lemma lt_Ord: "j<i ==> Ord(j)"
201 by (erule ltE, assumption)
203 lemma lt_Ord2: "j<i ==> Ord(i)"
204 by (erule ltE, assumption)
206 (* "ja le j ==> Ord(j)" *)
207 lemmas le_Ord2 = lt_Ord2 [THEN Ord_succD]
210 lemmas lt0E = not_lt0 [THEN notE, elim!]
212 lemma lt_trans: "[| i<j; j<k |] ==> i<k"
213 by (blast intro!: ltI elim!: ltE intro: Ord_trans)
215 lemma lt_not_sym: "i<j ==> ~ (j<i)"
216 apply (unfold lt_def)
217 apply (blast elim: mem_asym)
220 (* [| i<j; ~P ==> j<i |] ==> P *)
221 lemmas lt_asym = lt_not_sym [THEN swap]
223 lemma lt_irrefl [elim!]: "i<i ==> P"
224 by (blast intro: lt_asym)
226 lemma lt_not_refl: "~ i<i"
228 apply (erule lt_irrefl)
232 (** le is less than or equals; recall i le j abbrevs i<succ(j) !! **)
234 lemma le_iff: "i le j <-> i<j | (i=j & Ord(j))"
235 by (unfold lt_def, blast)
237 (*Equivalently, i<j ==> i < succ(j)*)
238 lemma leI: "i<j ==> i le j"
239 by (simp (no_asm_simp) add: le_iff)
241 lemma le_eqI: "[| i=j; Ord(j) |] ==> i le j"
242 by (simp (no_asm_simp) add: le_iff)
244 lemmas le_refl = refl [THEN le_eqI]
246 lemma le_refl_iff [iff]: "i le i <-> Ord(i)"
247 by (simp (no_asm_simp) add: lt_not_refl le_iff)
249 lemma leCI: "(~ (i=j & Ord(j)) ==> i<j) ==> i le j"
250 by (simp add: le_iff, blast)
253 "[| i le j; i<j ==> P; [| i=j; Ord(j) |] ==> P |] ==> P"
254 by (simp add: le_iff, blast)
256 lemma le_anti_sym: "[| i le j; j le i |] ==> i=j"
257 apply (simp add: le_iff)
258 apply (blast elim: lt_asym)
261 lemma le0_iff [simp]: "i le 0 <-> i=0"
262 by (blast elim!: leE)
264 lemmas le0D = le0_iff [THEN iffD1, dest!]
266 subsection{*Natural Deduction Rules for Memrel*}
268 (*The lemmas MemrelI/E give better speed than [iff] here*)
269 lemma Memrel_iff [simp]: "<a,b> : Memrel(A) <-> a:b & a:A & b:A"
270 by (unfold Memrel_def, blast)
272 lemma MemrelI [intro!]: "[| a: b; a: A; b: A |] ==> <a,b> : Memrel(A)"
275 lemma MemrelE [elim!]:
276 "[| <a,b> : Memrel(A);
277 [| a: A; b: A; a:b |] ==> P |]
281 lemma Memrel_type: "Memrel(A) <= A*A"
282 by (unfold Memrel_def, blast)
284 lemma Memrel_mono: "A<=B ==> Memrel(A) <= Memrel(B)"
285 by (unfold Memrel_def, blast)
287 lemma Memrel_0 [simp]: "Memrel(0) = 0"
288 by (unfold Memrel_def, blast)
290 lemma Memrel_1 [simp]: "Memrel(1) = 0"
291 by (unfold Memrel_def, blast)
293 lemma relation_Memrel: "relation(Memrel(A))"
294 by (simp add: relation_def Memrel_def, blast)
296 (*The membership relation (as a set) is well-founded.
297 Proof idea: show A<=B by applying the foundation axiom to A-B *)
298 lemma wf_Memrel: "wf(Memrel(A))"
299 apply (unfold wf_def)
300 apply (rule foundation [THEN disjE, THEN allI], erule disjI1, blast)
303 text{*The premise @{term "Ord(i)"} does not suffice.*}
305 "Ord(i) ==> trans(Memrel(i))"
306 by (unfold Ord_def Transset_def trans_def, blast)
308 text{*However, the following premise is strong enough.*}
309 lemma Transset_trans_Memrel:
310 "\<forall>j\<in>i. Transset(j) ==> trans(Memrel(i))"
311 by (unfold Transset_def trans_def, blast)
313 (*If Transset(A) then Memrel(A) internalizes the membership relation below A*)
314 lemma Transset_Memrel_iff:
315 "Transset(A) ==> <a,b> : Memrel(A) <-> a:b & b:A"
316 by (unfold Transset_def, blast)
319 subsection{*Transfinite Induction*}
321 (*Epsilon induction over a transitive set*)
322 lemma Transset_induct:
323 "[| i: k; Transset(k);
324 !!x.[| x: k; ALL y:x. P(y) |] ==> P(x) |]
326 apply (simp add: Transset_def)
327 apply (erule wf_Memrel [THEN wf_induct2], blast+)
330 (*Induction over an ordinal*)
331 lemmas Ord_induct [consumes 2] = Transset_induct [OF _ Ord_is_Transset]
332 lemmas Ord_induct_rule = Ord_induct [rule_format, consumes 2]
334 (*Induction over the class of ordinals -- a useful corollary of Ord_induct*)
336 lemma trans_induct [consumes 1]:
338 !!x.[| Ord(x); ALL y:x. P(y) |] ==> P(x) |]
340 apply (rule Ord_succ [THEN succI1 [THEN Ord_induct]], assumption)
341 apply (blast intro: Ord_succ [THEN Ord_in_Ord])
344 lemmas trans_induct_rule = trans_induct [rule_format, consumes 1]
347 (*** Fundamental properties of the epsilon ordering (< on ordinals) ***)
350 subsubsection{*Proving That < is a Linear Ordering on the Ordinals*}
352 lemma Ord_linear [rule_format]:
353 "Ord(i) ==> (ALL j. Ord(j) --> i:j | i=j | j:i)"
354 apply (erule trans_induct)
355 apply (rule impI [THEN allI])
356 apply (erule_tac i=j in trans_induct)
357 apply (blast dest: Ord_trans)
360 (*The trichotomy law for ordinals!*)
362 "[| Ord(i); Ord(j); i<j ==> P; i=j ==> P; j<i ==> P |] ==> P"
363 apply (simp add: lt_def)
364 apply (rule_tac i1=i and j1=j in Ord_linear [THEN disjE], blast+)
368 "[| Ord(i); Ord(j); i<j ==> P; j le i ==> P |] ==> P"
369 apply (rule_tac i = i and j = j in Ord_linear_lt)
370 apply (blast intro: leI le_eqI sym ) +
374 "[| Ord(i); Ord(j); i le j ==> P; j le i ==> P |] ==> P"
375 apply (rule_tac i = i and j = j in Ord_linear_lt)
376 apply (blast intro: leI le_eqI ) +
379 lemma le_imp_not_lt: "j le i ==> ~ i<j"
380 by (blast elim!: leE elim: lt_asym)
382 lemma not_lt_imp_le: "[| ~ i<j; Ord(i); Ord(j) |] ==> j le i"
383 by (rule_tac i = i and j = j in Ord_linear2, auto)
385 subsubsection{*Some Rewrite Rules for <, le*}
387 lemma Ord_mem_iff_lt: "Ord(j) ==> i:j <-> i<j"
388 by (unfold lt_def, blast)
390 lemma not_lt_iff_le: "[| Ord(i); Ord(j) |] ==> ~ i<j <-> j le i"
391 by (blast dest: le_imp_not_lt not_lt_imp_le)
393 lemma not_le_iff_lt: "[| Ord(i); Ord(j) |] ==> ~ i le j <-> j<i"
394 by (simp (no_asm_simp) add: not_lt_iff_le [THEN iff_sym])
396 (*This is identical to 0<succ(i) *)
397 lemma Ord_0_le: "Ord(i) ==> 0 le i"
398 by (erule not_lt_iff_le [THEN iffD1], auto)
400 lemma Ord_0_lt: "[| Ord(i); i~=0 |] ==> 0<i"
401 apply (erule not_le_iff_lt [THEN iffD1])
402 apply (rule Ord_0, blast)
405 lemma Ord_0_lt_iff: "Ord(i) ==> i~=0 <-> 0<i"
406 by (blast intro: Ord_0_lt)
409 subsection{*Results about Less-Than or Equals*}
411 (** For ordinals, j<=i (subset) implies j le i (less-than or equals) **)
413 lemma zero_le_succ_iff [iff]: "0 le succ(x) <-> Ord(x)"
414 by (blast intro: Ord_0_le elim: ltE)
416 lemma subset_imp_le: "[| j<=i; Ord(i); Ord(j) |] ==> j le i"
417 apply (rule not_lt_iff_le [THEN iffD1], assumption+)
418 apply (blast elim: ltE mem_irrefl)
421 lemma le_imp_subset: "i le j ==> i<=j"
422 by (blast dest: OrdmemD elim: ltE leE)
424 lemma le_subset_iff: "j le i <-> j<=i & Ord(i) & Ord(j)"
425 by (blast dest: subset_imp_le le_imp_subset elim: ltE)
427 lemma le_succ_iff: "i le succ(j) <-> i le j | i=succ(j) & Ord(i)"
428 apply (simp (no_asm) add: le_iff)
432 (*Just a variant of subset_imp_le*)
433 lemma all_lt_imp_le: "[| Ord(i); Ord(j); !!x. x<j ==> x<i |] ==> j le i"
434 by (blast intro: not_lt_imp_le dest: lt_irrefl)
436 subsubsection{*Transitivity Laws*}
438 lemma lt_trans1: "[| i le j; j<k |] ==> i<k"
439 by (blast elim!: leE intro: lt_trans)
441 lemma lt_trans2: "[| i<j; j le k |] ==> i<k"
442 by (blast elim!: leE intro: lt_trans)
444 lemma le_trans: "[| i le j; j le k |] ==> i le k"
445 by (blast intro: lt_trans1)
447 lemma succ_leI: "i<j ==> succ(i) le j"
448 apply (rule not_lt_iff_le [THEN iffD1])
449 apply (blast elim: ltE leE lt_asym)+
452 (*Identical to succ(i) < succ(j) ==> i<j *)
453 lemma succ_leE: "succ(i) le j ==> i<j"
454 apply (rule not_le_iff_lt [THEN iffD1])
455 apply (blast elim: ltE leE lt_asym)+
458 lemma succ_le_iff [iff]: "succ(i) le j <-> i<j"
459 by (blast intro: succ_leI succ_leE)
461 lemma succ_le_imp_le: "succ(i) le succ(j) ==> i le j"
462 by (blast dest!: succ_leE)
464 lemma lt_subset_trans: "[| i <= j; j<k; Ord(i) |] ==> i<k"
465 apply (rule subset_imp_le [THEN lt_trans1])
466 apply (blast intro: elim: ltE) +
469 lemma lt_imp_0_lt: "j<i ==> 0<i"
470 by (blast intro: lt_trans1 Ord_0_le [OF lt_Ord])
472 lemma succ_lt_iff: "succ(i) < j <-> i<j & succ(i) \<noteq> j"
474 apply (blast intro: lt_trans le_refl dest: lt_Ord)
476 apply (rule not_le_iff_lt [THEN iffD1])
477 apply (blast intro: lt_Ord2)
479 apply (simp add: lt_Ord lt_Ord2 le_iff)
480 apply (blast dest: lt_asym)
483 lemma Ord_succ_mem_iff: "Ord(j) ==> succ(i) \<in> succ(j) <-> i\<in>j"
484 apply (insert succ_le_iff [of i j])
485 apply (simp add: lt_def)
488 subsubsection{*Union and Intersection*}
490 lemma Un_upper1_le: "[| Ord(i); Ord(j) |] ==> i le i Un j"
491 by (rule Un_upper1 [THEN subset_imp_le], auto)
493 lemma Un_upper2_le: "[| Ord(i); Ord(j) |] ==> j le i Un j"
494 by (rule Un_upper2 [THEN subset_imp_le], auto)
496 (*Replacing k by succ(k') yields the similar rule for le!*)
497 lemma Un_least_lt: "[| i<k; j<k |] ==> i Un j < k"
498 apply (rule_tac i = i and j = j in Ord_linear_le)
499 apply (auto simp add: Un_commute le_subset_iff subset_Un_iff lt_Ord)
502 lemma Un_least_lt_iff: "[| Ord(i); Ord(j) |] ==> i Un j < k <-> i<k & j<k"
503 apply (safe intro!: Un_least_lt)
504 apply (rule_tac [2] Un_upper2_le [THEN lt_trans1])
505 apply (rule Un_upper1_le [THEN lt_trans1], auto)
508 lemma Un_least_mem_iff:
509 "[| Ord(i); Ord(j); Ord(k) |] ==> i Un j : k <-> i:k & j:k"
510 apply (insert Un_least_lt_iff [of i j k])
511 apply (simp add: lt_def)
514 (*Replacing k by succ(k') yields the similar rule for le!*)
515 lemma Int_greatest_lt: "[| i<k; j<k |] ==> i Int j < k"
516 apply (rule_tac i = i and j = j in Ord_linear_le)
517 apply (auto simp add: Int_commute le_subset_iff subset_Int_iff lt_Ord)
521 "[| Ord(i); Ord(j) |] ==> i \<union> j = (if j<i then i else j)"
522 by (simp add: not_lt_iff_le le_imp_subset leI
523 subset_Un_iff [symmetric] subset_Un_iff2 [symmetric])
525 lemma succ_Un_distrib:
526 "[| Ord(i); Ord(j) |] ==> succ(i \<union> j) = succ(i) \<union> succ(j)"
527 by (simp add: Ord_Un_if lt_Ord le_Ord2)
530 "[| Ord(i); Ord(j) |] ==> k < i \<union> j <-> k < i | k < j";
531 apply (simp add: Ord_Un_if not_lt_iff_le)
532 apply (blast intro: leI lt_trans2)+
536 "[| Ord(i); Ord(j) |] ==> k \<le> i \<union> j <-> k \<le> i | k \<le> j";
537 by (simp add: succ_Un_distrib lt_Un_iff [symmetric])
539 lemma Un_upper1_lt: "[|k < i; Ord(j)|] ==> k < i Un j"
540 by (simp add: lt_Un_iff lt_Ord2)
542 lemma Un_upper2_lt: "[|k < j; Ord(i)|] ==> k < i Un j"
543 by (simp add: lt_Un_iff lt_Ord2)
545 (*See also Transset_iff_Union_succ*)
546 lemma Ord_Union_succ_eq: "Ord(i) ==> \<Union>(succ(i)) = i"
547 by (blast intro: Ord_trans)
550 subsection{*Results about Limits*}
552 lemma Ord_Union [intro,simp,TC]: "[| !!i. i:A ==> Ord(i) |] ==> Ord(Union(A))"
553 apply (rule Ord_is_Transset [THEN Transset_Union_family, THEN OrdI])
554 apply (blast intro: Ord_contains_Transset)+
557 lemma Ord_UN [intro,simp,TC]:
558 "[| !!x. x:A ==> Ord(B(x)) |] ==> Ord(\<Union>x\<in>A. B(x))"
559 by (rule Ord_Union, blast)
561 lemma Ord_Inter [intro,simp,TC]:
562 "[| !!i. i:A ==> Ord(i) |] ==> Ord(Inter(A))"
563 apply (rule Transset_Inter_family [THEN OrdI])
564 apply (blast intro: Ord_is_Transset)
565 apply (simp add: Inter_def)
566 apply (blast intro: Ord_contains_Transset)
569 lemma Ord_INT [intro,simp,TC]:
570 "[| !!x. x:A ==> Ord(B(x)) |] ==> Ord(\<Inter>x\<in>A. B(x))"
571 by (rule Ord_Inter, blast)
574 (* No < version; consider (\<Union>i\<in>nat.i)=nat *)
576 "[| Ord(i); !!x. x:A ==> b(x) le i |] ==> (\<Union>x\<in>A. b(x)) le i"
577 apply (rule le_imp_subset [THEN UN_least, THEN subset_imp_le])
578 apply (blast intro: Ord_UN elim: ltE)+
581 lemma UN_succ_least_lt:
582 "[| j<i; !!x. x:A ==> b(x)<j |] ==> (\<Union>x\<in>A. succ(b(x))) < i"
583 apply (rule ltE, assumption)
584 apply (rule UN_least_le [THEN lt_trans2])
585 apply (blast intro: succ_leI)+
589 "[| a\<in>A; i < b(a); Ord(\<Union>x\<in>A. b(x)) |] ==> i < (\<Union>x\<in>A. b(x))"
590 by (unfold lt_def, blast)
593 "[| a: A; i le b(a); Ord(\<Union>x\<in>A. b(x)) |] ==> i le (\<Union>x\<in>A. b(x))"
595 apply (rule le_imp_subset [THEN subset_trans, THEN subset_imp_le])
596 apply (blast intro: lt_Ord UN_upper)+
599 lemma lt_Union_iff: "\<forall>i\<in>A. Ord(i) ==> (j < \<Union>(A)) <-> (\<exists>i\<in>A. j<i)"
600 by (auto simp: lt_def Ord_Union)
602 lemma Union_upper_le:
603 "[| j: J; i\<le>j; Ord(\<Union>(J)) |] ==> i \<le> \<Union>J"
604 apply (subst Union_eq_UN)
605 apply (rule UN_upper_le, auto)
608 lemma le_implies_UN_le_UN:
609 "[| !!x. x:A ==> c(x) le d(x) |] ==> (\<Union>x\<in>A. c(x)) le (\<Union>x\<in>A. d(x))"
610 apply (rule UN_least_le)
611 apply (rule_tac [2] UN_upper_le)
612 apply (blast intro: Ord_UN le_Ord2)+
615 lemma Ord_equality: "Ord(i) ==> (\<Union>y\<in>i. succ(y)) = i"
616 by (blast intro: Ord_trans)
618 (*Holds for all transitive sets, not just ordinals*)
619 lemma Ord_Union_subset: "Ord(i) ==> Union(i) <= i"
620 by (blast intro: Ord_trans)
623 subsection{*Limit Ordinals -- General Properties*}
625 lemma Limit_Union_eq: "Limit(i) ==> Union(i) = i"
626 apply (unfold Limit_def)
627 apply (fast intro!: ltI elim!: ltE elim: Ord_trans)
630 lemma Limit_is_Ord: "Limit(i) ==> Ord(i)"
631 apply (unfold Limit_def)
632 apply (erule conjunct1)
635 lemma Limit_has_0: "Limit(i) ==> 0 < i"
636 apply (unfold Limit_def)
637 apply (erule conjunct2 [THEN conjunct1])
640 lemma Limit_nonzero: "Limit(i) ==> i ~= 0"
641 by (drule Limit_has_0, blast)
643 lemma Limit_has_succ: "[| Limit(i); j<i |] ==> succ(j) < i"
644 by (unfold Limit_def, blast)
646 lemma Limit_succ_lt_iff [simp]: "Limit(i) ==> succ(j) < i <-> (j<i)"
647 apply (safe intro!: Limit_has_succ)
649 apply (blast intro: lt_trans)
652 lemma zero_not_Limit [iff]: "~ Limit(0)"
653 by (simp add: Limit_def)
655 lemma Limit_has_1: "Limit(i) ==> 1 < i"
656 by (blast intro: Limit_has_0 Limit_has_succ)
658 lemma increasing_LimitI: "[| 0<l; \<forall>x\<in>l. \<exists>y\<in>l. x<y |] ==> Limit(l)"
659 apply (unfold Limit_def, simp add: lt_Ord2, clarify)
660 apply (drule_tac i=y in ltD)
661 apply (blast intro: lt_trans1 [OF _ ltI] lt_Ord2)
664 lemma non_succ_LimitI:
665 "[| 0<i; ALL y. succ(y) ~= i |] ==> Limit(i)"
666 apply (unfold Limit_def)
667 apply (safe del: subsetI)
668 apply (rule_tac [2] not_le_iff_lt [THEN iffD1])
669 apply (simp_all add: lt_Ord lt_Ord2)
670 apply (blast elim: leE lt_asym)
673 lemma succ_LimitE [elim!]: "Limit(succ(i)) ==> P"
674 apply (rule lt_irrefl)
675 apply (rule Limit_has_succ, assumption)
676 apply (erule Limit_is_Ord [THEN Ord_succD, THEN le_refl])
679 lemma not_succ_Limit [simp]: "~ Limit(succ(i))"
682 lemma Limit_le_succD: "[| Limit(i); i le succ(j) |] ==> i le j"
683 by (blast elim!: leE)
686 subsubsection{*Traditional 3-Way Case Analysis on Ordinals*}
688 lemma Ord_cases_disj: "Ord(i) ==> i=0 | (EX j. Ord(j) & i=succ(j)) | Limit(i)"
689 by (blast intro!: non_succ_LimitI Ord_0_lt)
694 !!j. [| Ord(j); i=succ(j) |] ==> P;
697 by (drule Ord_cases_disj, blast)
699 lemma trans_induct3 [case_names 0 succ limit, consumes 1]:
702 !!x. [| Ord(x); P(x) |] ==> P(succ(x));
703 !!x. [| Limit(x); ALL y:x. P(y) |] ==> P(x)
705 apply (erule trans_induct)
706 apply (erule Ord_cases, blast+)
709 lemmas trans_induct3_rule = trans_induct3 [rule_format, case_names 0 succ limit, consumes 1]
711 text{*A set of ordinals is either empty, contains its own union, or its
712 union is a limit ordinal.*}
714 "\<forall>i\<in>I. Ord(i) ==> I=0 \<or> \<Union>(I) \<in> I \<or> (\<Union>(I) \<notin> I \<and> Limit(\<Union>(I)))"
715 apply (clarify elim!: not_emptyE)
716 apply (cases "\<Union>(I)" rule: Ord_cases)
717 apply (blast intro: Ord_Union)
718 apply (blast intro: subst_elem)
720 apply (clarify elim!: equalityE succ_subsetE)
721 apply (simp add: Union_subset_iff)
722 apply (subgoal_tac "B = succ(j)", blast)
723 apply (rule le_anti_sym)
724 apply (simp add: le_subset_iff)
725 apply (simp add: ltI)
728 text{*If the union of a set of ordinals is a successor, then it is
729 an element of that set.*}
730 lemma Ord_Union_eq_succD: "[|\<forall>x\<in>X. Ord(x); \<Union>X = succ(j)|] ==> succ(j) \<in> X"
731 by (drule Ord_set_cases, auto)
733 lemma Limit_Union [rule_format]: "[| I \<noteq> 0; \<forall>i\<in>I. Limit(i) |] ==> Limit(\<Union>I)"
734 apply (simp add: Limit_def lt_def)
735 apply (blast intro!: equalityI)
740 val Memrel_def = thm "Memrel_def";
741 val Transset_def = thm "Transset_def";
742 val Ord_def = thm "Ord_def";
743 val lt_def = thm "lt_def";
744 val Limit_def = thm "Limit_def";
746 val Transset_iff_Pow = thm "Transset_iff_Pow";
747 val Transset_iff_Union_succ = thm "Transset_iff_Union_succ";
748 val Transset_iff_Union_subset = thm "Transset_iff_Union_subset";
749 val Transset_doubleton_D = thm "Transset_doubleton_D";
750 val Transset_Pair_D = thm "Transset_Pair_D";
751 val Transset_includes_domain = thm "Transset_includes_domain";
752 val Transset_includes_range = thm "Transset_includes_range";
753 val Transset_0 = thm "Transset_0";
754 val Transset_Un = thm "Transset_Un";
755 val Transset_Int = thm "Transset_Int";
756 val Transset_succ = thm "Transset_succ";
757 val Transset_Pow = thm "Transset_Pow";
758 val Transset_Union = thm "Transset_Union";
759 val Transset_Union_family = thm "Transset_Union_family";
760 val Transset_Inter_family = thm "Transset_Inter_family";
761 val OrdI = thm "OrdI";
762 val Ord_is_Transset = thm "Ord_is_Transset";
763 val Ord_contains_Transset = thm "Ord_contains_Transset";
764 val Ord_in_Ord = thm "Ord_in_Ord";
765 val Ord_succD = thm "Ord_succD";
766 val Ord_subset_Ord = thm "Ord_subset_Ord";
767 val OrdmemD = thm "OrdmemD";
768 val Ord_trans = thm "Ord_trans";
769 val Ord_succ_subsetI = thm "Ord_succ_subsetI";
770 val Ord_0 = thm "Ord_0";
771 val Ord_succ = thm "Ord_succ";
772 val Ord_1 = thm "Ord_1";
773 val Ord_succ_iff = thm "Ord_succ_iff";
774 val Ord_Un = thm "Ord_Un";
775 val Ord_Int = thm "Ord_Int";
776 val Ord_Inter = thm "Ord_Inter";
777 val Ord_INT = thm "Ord_INT";
778 val ON_class = thm "ON_class";
782 val not_lt0 = thm "not_lt0";
783 val lt_Ord = thm "lt_Ord";
784 val lt_Ord2 = thm "lt_Ord2";
785 val le_Ord2 = thm "le_Ord2";
786 val lt0E = thm "lt0E";
787 val lt_trans = thm "lt_trans";
788 val lt_not_sym = thm "lt_not_sym";
789 val lt_asym = thm "lt_asym";
790 val lt_irrefl = thm "lt_irrefl";
791 val lt_not_refl = thm "lt_not_refl";
792 val le_iff = thm "le_iff";
794 val le_eqI = thm "le_eqI";
795 val le_refl = thm "le_refl";
796 val le_refl_iff = thm "le_refl_iff";
797 val leCI = thm "leCI";
799 val le_anti_sym = thm "le_anti_sym";
800 val le0_iff = thm "le0_iff";
801 val le0D = thm "le0D";
802 val Memrel_iff = thm "Memrel_iff";
803 val MemrelI = thm "MemrelI";
804 val MemrelE = thm "MemrelE";
805 val Memrel_type = thm "Memrel_type";
806 val Memrel_mono = thm "Memrel_mono";
807 val Memrel_0 = thm "Memrel_0";
808 val Memrel_1 = thm "Memrel_1";
809 val wf_Memrel = thm "wf_Memrel";
810 val trans_Memrel = thm "trans_Memrel";
811 val Transset_Memrel_iff = thm "Transset_Memrel_iff";
812 val Transset_induct = thm "Transset_induct";
813 val Ord_induct = thm "Ord_induct";
814 val trans_induct = thm "trans_induct";
815 val Ord_linear = thm "Ord_linear";
816 val Ord_linear_lt = thm "Ord_linear_lt";
817 val Ord_linear2 = thm "Ord_linear2";
818 val Ord_linear_le = thm "Ord_linear_le";
819 val le_imp_not_lt = thm "le_imp_not_lt";
820 val not_lt_imp_le = thm "not_lt_imp_le";
821 val Ord_mem_iff_lt = thm "Ord_mem_iff_lt";
822 val not_lt_iff_le = thm "not_lt_iff_le";
823 val not_le_iff_lt = thm "not_le_iff_lt";
824 val Ord_0_le = thm "Ord_0_le";
825 val Ord_0_lt = thm "Ord_0_lt";
826 val Ord_0_lt_iff = thm "Ord_0_lt_iff";
827 val zero_le_succ_iff = thm "zero_le_succ_iff";
828 val subset_imp_le = thm "subset_imp_le";
829 val le_imp_subset = thm "le_imp_subset";
830 val le_subset_iff = thm "le_subset_iff";
831 val le_succ_iff = thm "le_succ_iff";
832 val all_lt_imp_le = thm "all_lt_imp_le";
833 val lt_trans1 = thm "lt_trans1";
834 val lt_trans2 = thm "lt_trans2";
835 val le_trans = thm "le_trans";
836 val succ_leI = thm "succ_leI";
837 val succ_leE = thm "succ_leE";
838 val succ_le_iff = thm "succ_le_iff";
839 val succ_le_imp_le = thm "succ_le_imp_le";
840 val lt_subset_trans = thm "lt_subset_trans";
841 val Un_upper1_le = thm "Un_upper1_le";
842 val Un_upper2_le = thm "Un_upper2_le";
843 val Un_least_lt = thm "Un_least_lt";
844 val Un_least_lt_iff = thm "Un_least_lt_iff";
845 val Un_least_mem_iff = thm "Un_least_mem_iff";
846 val Int_greatest_lt = thm "Int_greatest_lt";
847 val Ord_Union = thm "Ord_Union";
848 val Ord_UN = thm "Ord_UN";
849 val UN_least_le = thm "UN_least_le";
850 val UN_succ_least_lt = thm "UN_succ_least_lt";
851 val UN_upper_le = thm "UN_upper_le";
852 val le_implies_UN_le_UN = thm "le_implies_UN_le_UN";
853 val Ord_equality = thm "Ord_equality";
854 val Ord_Union_subset = thm "Ord_Union_subset";
855 val Limit_Union_eq = thm "Limit_Union_eq";
856 val Limit_is_Ord = thm "Limit_is_Ord";
857 val Limit_has_0 = thm "Limit_has_0";
858 val Limit_has_succ = thm "Limit_has_succ";
859 val non_succ_LimitI = thm "non_succ_LimitI";
860 val succ_LimitE = thm "succ_LimitE";
861 val not_succ_Limit = thm "not_succ_Limit";
862 val Limit_le_succD = thm "Limit_le_succD";
863 val Ord_cases_disj = thm "Ord_cases_disj";
864 val Ord_cases = thm "Ord_cases";
865 val trans_induct3 = thm "trans_induct3";