src/ZF/CardinalArith.thy
changeset 13269 3ba9be497c33
parent 13244 7b37e218f298
child 13328 703de709a64b
equal deleted inserted replaced
13268:240509babf00 13269:3ba9be497c33
   465 
   465 
   466 (*** An infinite cardinal equals its square (Kunen, Thm 10.12, page 29) ***)
   466 (*** An infinite cardinal equals its square (Kunen, Thm 10.12, page 29) ***)
   467 
   467 
   468 (*A general fact about ordermap*)
   468 (*A general fact about ordermap*)
   469 lemma ordermap_eqpoll_pred:
   469 lemma ordermap_eqpoll_pred:
   470     "[| well_ord(A,r);  x:A |] ==> ordermap(A,r)`x \<approx> pred(A,x,r)"
   470     "[| well_ord(A,r);  x:A |] ==> ordermap(A,r)`x \<approx> Order.pred(A,x,r)"
   471 apply (unfold eqpoll_def)
   471 apply (unfold eqpoll_def)
   472 apply (rule exI)
   472 apply (rule exI)
   473 apply (simp add: ordermap_eq_image well_ord_is_wf)
   473 apply (simp add: ordermap_eq_image well_ord_is_wf)
   474 apply (erule ordermap_bij [THEN bij_is_inj, THEN restrict_bij, 
   474 apply (erule ordermap_bij [THEN bij_is_inj, THEN restrict_bij, 
   475                            THEN bij_converse_bij])
   475                            THEN bij_converse_bij])
   501 apply (safe elim!: mem_irrefl intro!: Un_upper1_le Un_upper2_le)
   501 apply (safe elim!: mem_irrefl intro!: Un_upper1_le Un_upper2_le)
   502 apply (simp_all add: lt_def succI2)
   502 apply (simp_all add: lt_def succI2)
   503 done
   503 done
   504 
   504 
   505 lemma pred_csquare_subset: 
   505 lemma pred_csquare_subset: 
   506     "z<K ==> pred(K*K, <z,z>, csquare_rel(K)) <= succ(z)*succ(z)"
   506     "z<K ==> Order.pred(K*K, <z,z>, csquare_rel(K)) <= succ(z)*succ(z)"
   507 apply (unfold Order.pred_def)
   507 apply (unfold Order.pred_def)
   508 apply (safe del: SigmaI succCI)
   508 apply (safe del: SigmaI succCI)
   509 apply (erule csquareD [THEN conjE])
   509 apply (erule csquareD [THEN conjE])
   510 apply (unfold lt_def, auto) 
   510 apply (unfold lt_def, auto) 
   511 done
   511 done