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Theorem zorn2 8882
Description: Zorn's Lemma of [Monk1] p. 117. This theorem is equivalent to the Axiom of Choice and states that every partially ordered set  A (with an ordering relation  R) in which every totally ordered subset has an upper bound, contains at least one maximal element. The main proof consists of lemmas zorn2lem1 8872 through zorn2lem7 8878; this final piece mainly changes bound variables to eliminate the hypotheses of zorn2lem7 8878. (Contributed by NM, 6-Apr-1997.) (Revised by Mario Carneiro, 9-May-2015.)
Hypothesis
Ref Expression
zornn0.1  |-  A  e. 
_V
Assertion
Ref Expression
zorn2  |-  ( ( R  Po  A  /\  A. w ( ( w 
C_  A  /\  R  Or  w )  ->  E. x  e.  A  A. z  e.  w  ( z R x  \/  z  =  x ) ) )  ->  E. x  e.  A  A. y  e.  A  -.  x R y )
Distinct variable groups:    x, w, y, z, A    w, R, x, y, z

Proof of Theorem zorn2
StepHypRef Expression
1 zornn0.1 . . 3  |-  A  e. 
_V
2 numth3 8846 . . 3  |-  ( A  e.  _V  ->  A  e.  dom  card )
31, 2ax-mp 5 . 2  |-  A  e. 
dom  card
4 zorn2g 8879 . 2  |-  ( ( A  e.  dom  card  /\  R  Po  A  /\  A. w ( ( w 
C_  A  /\  R  Or  w )  ->  E. x  e.  A  A. z  e.  w  ( z R x  \/  z  =  x ) ) )  ->  E. x  e.  A  A. y  e.  A  -.  x R y )
53, 4mp3an1 1311 1  |-  ( ( R  Po  A  /\  A. w ( ( w 
C_  A  /\  R  Or  w )  ->  E. x  e.  A  A. z  e.  w  ( z R x  \/  z  =  x ) ) )  ->  E. x  e.  A  A. y  e.  A  -.  x R y )
Colors of variables: wff setvar class
Syntax hints:   -. wn 3    -> wi 4    \/ wo 368    /\ wa 369   A.wal 1377    e. wcel 1767   A.wral 2814   E.wrex 2815   _Vcvv 3113    C_ wss 3476   class class class wbr 4447    Po wpo 4798    Or wor 4799   dom cdm 4999   cardccrd 8312
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1601  ax-4 1612  ax-5 1680  ax-6 1719  ax-7 1739  ax-8 1769  ax-9 1771  ax-10 1786  ax-11 1791  ax-12 1803  ax-13 1968  ax-ext 2445  ax-rep 4558  ax-sep 4568  ax-nul 4576  ax-pow 4625  ax-pr 4686  ax-un 6574  ax-ac2 8839
This theorem depends on definitions:  df-bi 185  df-or 370  df-an 371  df-3or 974  df-3an 975  df-tru 1382  df-ex 1597  df-nf 1600  df-sb 1712  df-eu 2279  df-mo 2280  df-clab 2453  df-cleq 2459  df-clel 2462  df-nfc 2617  df-ne 2664  df-ral 2819  df-rex 2820  df-reu 2821  df-rmo 2822  df-rab 2823  df-v 3115  df-sbc 3332  df-csb 3436  df-dif 3479  df-un 3481  df-in 3483  df-ss 3490  df-pss 3492  df-nul 3786  df-if 3940  df-pw 4012  df-sn 4028  df-pr 4030  df-tp 4032  df-op 4034  df-uni 4246  df-int 4283  df-iun 4327  df-br 4448  df-opab 4506  df-mpt 4507  df-tr 4541  df-eprel 4791  df-id 4795  df-po 4800  df-so 4801  df-fr 4838  df-se 4839  df-we 4840  df-ord 4881  df-on 4882  df-suc 4884  df-xp 5005  df-rel 5006  df-cnv 5007  df-co 5008  df-dm 5009  df-rn 5010  df-res 5011  df-ima 5012  df-iota 5549  df-fun 5588  df-fn 5589  df-f 5590  df-f1 5591  df-fo 5592  df-f1o 5593  df-fv 5594  df-isom 5595  df-riota 6243  df-recs 7039  df-en 7514  df-card 8316  df-ac 8493
This theorem is referenced by: (None)
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