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Theorem opthreg 6808
Description: Theorem for alternate representation of ordered pairs, requiring the Axiom of Regularity ax-reg 6795 (via the preleq 6807 step). See df-op 3265 for a description of other ordered pair representations. Exercise 34 of [Enderton] p. 207. (Contributed by NM, 16-Oct-1996.)
Hypotheses
Ref Expression
preleq.1  |-  A  e. 
_V
preleq.2  |-  B  e. 
_V
preleq.3  |-  C  e. 
_V
preleq.4  |-  D  e. 
_V
Assertion
Ref Expression
opthreg  |-  ( { A ,  { A ,  B } }  =  { C ,  { C ,  D } }  <->  ( A  =  C  /\  B  =  D ) )

Proof of Theorem opthreg
StepHypRef Expression
1 preleq.1 . . . . 5  |-  A  e. 
_V
21prid1 3345 . . . 4  |-  A  e. 
{ A ,  B }
3 preleq.3 . . . . 5  |-  C  e. 
_V
43prid1 3345 . . . 4  |-  C  e. 
{ C ,  D }
5 prex 3778 . . . . 5  |-  { A ,  B }  e.  _V
6 prex 3778 . . . . 5  |-  { C ,  D }  e.  _V
71, 5, 3, 6preleq 6807 . . . 4  |-  ( ( ( A  e.  { A ,  B }  /\  C  e.  { C ,  D } )  /\  { A ,  { A ,  B } }  =  { C ,  { C ,  D } } )  ->  ( A  =  C  /\  { A ,  B }  =  { C ,  D }
) )
82, 4, 7mpanl12 656 . . 3  |-  ( { A ,  { A ,  B } }  =  { C ,  { C ,  D } }  ->  ( A  =  C  /\  { A ,  B }  =  { C ,  D } ) )
9 preq1 3317 . . . . . 6  |-  ( A  =  C  ->  { A ,  B }  =  { C ,  B }
)
109eqeq1d 2073 . . . . 5  |-  ( A  =  C  ->  ( { A ,  B }  =  { C ,  D } 
<->  { C ,  B }  =  { C ,  D } ) )
11 preleq.2 . . . . . 6  |-  B  e. 
_V
12 preleq.4 . . . . . 6  |-  D  e. 
_V
1311, 12preqr2 3394 . . . . 5  |-  ( { C ,  B }  =  { C ,  D }  ->  B  =  D )
1410, 13syl6bi 217 . . . 4  |-  ( A  =  C  ->  ( { A ,  B }  =  { C ,  D }  ->  B  =  D ) )
1514imdistani 664 . . 3  |-  ( ( A  =  C  /\  { A ,  B }  =  { C ,  D } )  ->  ( A  =  C  /\  B  =  D )
)
168, 15syl 15 . 2  |-  ( { A ,  { A ,  B } }  =  { C ,  { C ,  D } }  ->  ( A  =  C  /\  B  =  D )
)
17 preq1 3317 . . . 4  |-  ( A  =  C  ->  { A ,  { A ,  B } }  =  { C ,  { A ,  B } } )
1817adantr 445 . . 3  |-  ( ( A  =  C  /\  B  =  D )  ->  { A ,  { A ,  B } }  =  { C ,  { A ,  B } } )
19 preq12 3319 . . . 4  |-  ( ( A  =  C  /\  B  =  D )  ->  { A ,  B }  =  { C ,  D } )
2019preq2d 3324 . . 3  |-  ( ( A  =  C  /\  B  =  D )  ->  { C ,  { A ,  B } }  =  { C ,  { C ,  D } } )
2118, 20eqtrd 2097 . 2  |-  ( ( A  =  C  /\  B  =  D )  ->  { A ,  { A ,  B } }  =  { C ,  { C ,  D } } )
2216, 21impbii 178 1  |-  ( { A ,  { A ,  B } }  =  { C ,  { C ,  D } }  <->  ( A  =  C  /\  B  =  D ) )
Colors of variables: wff set class
Syntax hints:    <-> wb 174    /\ wa 356    = wceq 1520    e. wcel 1522   _Vcvv 2476   {cpr 3257
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-5 1442  ax-6 1443  ax-7 1444  ax-gen 1445  ax-8 1524  ax-11 1525  ax-14 1527  ax-17 1529  ax-12o 1563  ax-10 1577  ax-9 1583  ax-4 1590  ax-16 1776  ax-ext 2047  ax-sep 3707  ax-nul 3715  ax-pr 3775  ax-reg 6795
This theorem depends on definitions:  df-bi 175  df-or 357  df-an 358  df-3an 898  df-ex 1447  df-sb 1737  df-eu 1959  df-mo 1960  df-clab 2053  df-cleq 2058  df-clel 2061  df-ne 2185  df-ral 2279  df-rex 2280  df-rab 2282  df-v 2478  df-sbc 2652  df-dif 2797  df-un 2799  df-in 2801  df-ss 2805  df-nul 3074  df-if 3183  df-sn 3262  df-pr 3263  df-op 3265  df-br 3593  df-opab 3647  df-eprel 3862  df-fr 3909
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