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Theorem zorn2 8128
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 8118 through zorn2lem7 8124; this final piece mainly changes bound variables to eliminate the hypotheses of zorn2lem7 8124. (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 8092 . . 3  |-  ( A  e.  _V  ->  A  e.  dom  card )
31, 2ax-mp 10 . 2  |-  A  e. 
dom  card
4 zorn2g 8125 . 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 1266 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 set class
Syntax hints:   -. wn 5    -> wi 6    \/ wo 359    /\ wa 360   A.wal 1528    = wceq 1624    e. wcel 1685   A.wral 2544   E.wrex 2545   _Vcvv 2789    C_ wss 3153   class class class wbr 4024    Po wpo 4311    Or wor 4312   dom cdm 4688   cardccrd 7563
This theorem was proved from axioms:  ax-1 7  ax-2 8  ax-3 9  ax-mp 10  ax-gen 1534  ax-5 1545  ax-17 1604  ax-9 1637  ax-8 1645  ax-13 1687  ax-14 1689  ax-6 1704  ax-7 1709  ax-11 1716  ax-12 1867  ax-ext 2265  ax-rep 4132  ax-sep 4142  ax-nul 4150  ax-pow 4187  ax-pr 4213  ax-un 4511  ax-ac2 8084
This theorem depends on definitions:  df-bi 179  df-or 361  df-an 362  df-3or 937  df-3an 938  df-tru 1312  df-ex 1530  df-nf 1533  df-sb 1632  df-eu 2148  df-mo 2149  df-clab 2271  df-cleq 2277  df-clel 2280  df-nfc 2409  df-ne 2449  df-ral 2549  df-rex 2550  df-reu 2551  df-rmo 2552  df-rab 2553  df-v 2791  df-sbc 2993  df-csb 3083  df-dif 3156  df-un 3158  df-in 3160  df-ss 3167  df-pss 3169  df-nul 3457  df-if 3567  df-pw 3628  df-sn 3647  df-pr 3648  df-tp 3649  df-op 3650  df-uni 3829  df-int 3864  df-iun 3908  df-br 4025  df-opab 4079  df-mpt 4080  df-tr 4115  df-eprel 4304  df-id 4308  df-po 4313  df-so 4314  df-fr 4351  df-se 4352  df-we 4353  df-ord 4394  df-on 4395  df-suc 4397  df-xp 4694  df-rel 4695  df-cnv 4696  df-co 4697  df-dm 4698  df-rn 4699  df-res 4700  df-ima 4701  df-fun 5223  df-fn 5224  df-f 5225  df-f1 5226  df-fo 5227  df-f1o 5228  df-fv 5229  df-isom 5230  df-iota 6252  df-riota 6299  df-recs 6383  df-en 6859  df-card 7567  df-ac 7738
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