Theorem sbth 6207

Description: The Schroder-Bernstein Theorem. This theorem gives the antisymmetry law for cardinal less than or equal. Translated out, it means that, if A is no larger than B and B is no larger than A, then Nc A = Nc B. Theorem XI.2.20 of [Rosser] p. 376. (Contributed by SF, 11-Mar-2015.)

Assertion

Ref	Expression
sbth	|- ((A e. NC /\ B e. NC ) -> ((A <_c B /\ B <_c A) -> A = B))

Proof of Theorem sbth

Dummy variables a b d g are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		brlecg 6113	. . . 4 |- ((A e. NC /\ B e. NC ) -> (A <_c B <-> E.g e. A E.b e. B g C_ b))
2		brlecg 6113	. . . . 5 |- ((B e. NC /\ A e. NC ) -> (B <_c A <-> E.d e. B E.a e. A d C_ a))
3	2	ancoms 439	. . . 4 |- ((A e. NC /\ B e. NC ) -> (B <_c A <-> E.d e. B E.a e. A d C_ a))
4	1, 3	anbi12d 691	. . 3 |- ((A e. NC /\ B e. NC ) -> ((A <_c B /\ B <_c A) <-> (E.g e. A E.b e. B g C_ b /\ E.d e. B E.a e. A d C_ a)))
5		reeanv 2779	. . . . 5 |- (E.b e. B E.a e. A (g C_ b /\ d C_ a) <-> (E.b e. B g C_ b /\ E.a e. A d C_ a))
6	5	2rexbii 2642	. . . 4 |- (E.g e. A E.d e. B E.b e. B E.a e. A (g C_ b /\ d C_ a) <-> E.g e. A E.d e. B (E.b e. B g C_ b /\ E.a e. A d C_ a))
7		reeanv 2779	. . . 4 |- (E.g e. A E.d e. B (E.b e. B g C_ b /\ E.a e. A d C_ a) <-> (E.g e. A E.b e. B g C_ b /\ E.d e. B E.a e. A d C_ a))
8	6, 7	bitri 240	. . 3 |- (E.g e. A E.d e. B E.b e. B E.a e. A (g C_ b /\ d C_ a) <-> (E.g e. A E.b e. B g C_ b /\ E.d e. B E.a e. A d C_ a))
9	4, 8	syl6bbr 254	. 2 |- ((A e. NC /\ B e. NC ) -> ((A <_c B /\ B <_c A) <-> E.g e. A E.d e. B E.b e. B E.a e. A (g C_ b /\ d C_ a)))
10		ncseqnc 6129	. . . . . 6 |- (A e. NC -> (A = Nc g <-> g e. A))
11		ncseqnc 6129	. . . . . 6 |- (B e. NC -> (B = Nc d <-> d e. B))
12	10, 11	bi2anan9 843	. . . . 5 |- ((A e. NC /\ B e. NC ) -> ((A = Nc g /\ B = Nc d) <-> (g e. A /\ d e. B)))
13	12	biimpar 471	. . . 4 |- (((A e. NC /\ B e. NC ) /\ (g e. A /\ d e. B)) -> (A = Nc g /\ B = Nc d))
14		simplr 731	. . . . . . . . . . 11 |- (((b ~~ d /\ a ~~ g) /\ (g C_ b /\ d C_ a)) -> a ~~ g)
15		ensym 6038	. . . . . . . . . . 11 |- (a ~~ g <-> g ~~ a)
16	14, 15	sylib 188	. . . . . . . . . 10 |- (((b ~~ d /\ a ~~ g) /\ (g C_ b /\ d C_ a)) -> g ~~ a)
17		simprl 732	. . . . . . . . . . 11 |- (((b ~~ d /\ a ~~ g) /\ (g C_ b /\ d C_ a)) -> g C_ b)
18		simpll 730	. . . . . . . . . . 11 |- (((b ~~ d /\ a ~~ g) /\ (g C_ b /\ d C_ a)) -> b ~~ d)
19		simprr 733	. . . . . . . . . . 11 |- (((b ~~ d /\ a ~~ g) /\ (g C_ b /\ d C_ a)) -> d C_ a)
20		sbthlem3 6206	. . . . . . . . . . 11 |- (((a ~~ g /\ g C_ b) /\ (b ~~ d /\ d C_ a)) -> a ~~ b)
21	14, 17, 18, 19, 20	syl22anc 1183	. . . . . . . . . 10 |- (((b ~~ d /\ a ~~ g) /\ (g C_ b /\ d C_ a)) -> a ~~ b)
22		entr 6039	. . . . . . . . . 10 |- ((g ~~ a /\ a ~~ b) -> g ~~ b)
23	16, 21, 22	syl2anc 642	. . . . . . . . 9 |- (((b ~~ d /\ a ~~ g) /\ (g C_ b /\ d C_ a)) -> g ~~ b)
24		entr 6039	. . . . . . . . 9 |- ((g ~~ b /\ b ~~ d) -> g ~~ d)
25	23, 18, 24	syl2anc 642	. . . . . . . 8 |- (((b ~~ d /\ a ~~ g) /\ (g C_ b /\ d C_ a)) -> g ~~ d)
26	25	ex 423	. . . . . . 7 |- ((b ~~ d /\ a ~~ g) -> ((g C_ b /\ d C_ a) -> g ~~ d))
27		elnc 6126	. . . . . . . 8 |- (b e. Nc d <-> b ~~ d)
28		elnc 6126	. . . . . . . 8 |- (a e. Nc g <-> a ~~ g)
29	27, 28	anbi12i 678	. . . . . . 7 |- ((b e. Nc d /\ a e. Nc g) <-> (b ~~ d /\ a ~~ g))
30		vex 2863	. . . . . . . . 9 |- g e. _V
31	30	eqnc 6128	. . . . . . . 8 |- ( Nc g = Nc d <-> g ~~ d)
32	31	imbi2i 303	. . . . . . 7 |- (((g C_ b /\ d C_ a) -> Nc g = Nc d) <-> ((g C_ b /\ d C_ a) -> g ~~ d))
33	26, 29, 32	3imtr4i 257	. . . . . 6 |- ((b e. Nc d /\ a e. Nc g) -> ((g C_ b /\ d C_ a) -> Nc g = Nc d))
34	33	rexlimivv 2744	. . . . 5 |- (E.b e. Nc dE.a e. Nc g(g C_ b /\ d C_ a) -> Nc g = Nc d)
35		rexeq 2809	. . . . . . 7 |- (B = Nc d -> (E.b e. B E.a e. A (g C_ b /\ d C_ a) <-> E.b e. Nc dE.a e. A (g C_ b /\ d C_ a)))
36		rexeq 2809	. . . . . . . 8 |- (A = Nc g -> (E.a e. A (g C_ b /\ d C_ a) <-> E.a e. Nc g(g C_ b /\ d C_ a)))
37	36	rexbidv 2636	. . . . . . 7 |- (A = Nc g -> (E.b e. Nc dE.a e. A (g C_ b /\ d C_ a) <-> E.b e. Nc dE.a e. Nc g(g C_ b /\ d C_ a)))
38	35, 37	sylan9bbr 681	. . . . . 6 |- ((A = Nc g /\ B = Nc d) -> (E.b e. B E.a e. A (g C_ b /\ d C_ a) <-> E.b e. Nc dE.a e. Nc g(g C_ b /\ d C_ a)))
39		eqeq12 2365	. . . . . 6 |- ((A = Nc g /\ B = Nc d) -> (A = B <-> Nc g = Nc d))
40	38, 39	imbi12d 311	. . . . 5 |- ((A = Nc g /\ B = Nc d) -> ((E.b e. B E.a e. A (g C_ b /\ d C_ a) -> A = B) <-> (E.b e. Nc dE.a e. Nc g(g C_ b /\ d C_ a) -> Nc g = Nc d)))
41	34, 40	mpbiri 224	. . . 4 |- ((A = Nc g /\ B = Nc d) -> (E.b e. B E.a e. A (g C_ b /\ d C_ a) -> A = B))
42	13, 41	syl 15	. . 3 |- (((A e. NC /\ B e. NC ) /\ (g e. A /\ d e. B)) -> (E.b e. B E.a e. A (g C_ b /\ d C_ a) -> A = B))
43	42	rexlimdvva 2746	. 2 |- ((A e. NC /\ B e. NC ) -> (E.g e. A E.d e. B E.b e. B E.a e. A (g C_ b /\ d C_ a) -> A = B))
44	9, 43	sylbid 206	1 |- ((A e. NC /\ B e. NC ) -> ((A <_c B /\ B <_c A) -> A = B))

Syntax hints:   -> wi 4   <-> wb 176   /\ wa 358   = wceq 1642   e. wcel 1710  E.wrex 2616   C_ wss 3258   class class class wbr 4640   ~~ cen 6029   NC cncs 6089   <__c clec 6090   Nc cnc 6092

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1546  ax-5 1557  ax-17 1616  ax-9 1654  ax-8 1675  ax-13 1712  ax-14 1714  ax-6 1729  ax-7 1734  ax-11 1746  ax-12 1925  ax-ext 2334  ax-nin 4079  ax-xp 4080  ax-cnv 4081  ax-1c 4082  ax-sset 4083  ax-si 4084  ax-ins2 4085  ax-ins3 4086  ax-typlower 4087  ax-sn 4088

This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-3or 935  df-3an 936  df-nan 1288  df-tru 1319  df-ex 1542  df-nf 1545  df-sb 1649  df-eu 2208  df-mo 2209  df-clab 2340  df-cleq 2346  df-clel 2349  df-nfc 2479  df-ne 2519  df-ral 2620  df-rex 2621  df-reu 2622  df-rmo 2623  df-rab 2624  df-v 2862  df-sbc 3048  df-nin 3212  df-compl 3213  df-in 3214  df-un 3215  df-dif 3216  df-symdif 3217  df-ss 3260  df-pss 3262  df-nul 3552  df-if 3664  df-pw 3725  df-sn 3742  df-pr 3743  df-uni 3893  df-int 3928  df-opk 4059  df-1c 4137  df-pw1 4138  df-uni1 4139  df-xpk 4186  df-cnvk 4187  df-ins2k 4188  df-ins3k 4189  df-imak 4190  df-cok 4191  df-p6 4192  df-sik 4193  df-ssetk 4194  df-imagek 4195  df-idk 4196  df-iota 4340  df-0c 4378  df-addc 4379  df-nnc 4380  df-fin 4381  df-lefin 4441  df-ltfin 4442  df-ncfin 4443  df-tfin 4444  df-evenfin 4445  df-oddfin 4446  df-sfin 4447  df-spfin 4448  df-phi 4566  df-op 4567  df-proj1 4568  df-proj2 4569  df-opab 4624  df-br 4641  df-1st 4724  df-swap 4725  df-sset 4726  df-co 4727  df-ima 4728  df-si 4729  df-id 4768  df-xp 4785  df-cnv 4786  df-rn 4787  df-dm 4788  df-res 4789  df-fun 4790  df-fn 4791  df-f 4792  df-f1 4793  df-fo 4794  df-f1o 4795  df-2nd 4798  df-txp 5737  df-fix 5741  df-ins2 5751  df-ins3 5753  df-image 5755  df-ins4 5757  df-si3 5759  df-funs 5761  df-fns 5763  df-clos1 5874  df-trans 5900  df-sym 5909  df-er 5910  df-ec 5948  df-qs 5952  df-en 6030  df-ncs 6099  df-lec 6100  df-nc 6102

This theorem is referenced by:  ltlenlec  6208  leltctr  6213  lecponc  6214  nclenn  6250  ncvsq  6257