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Theorem opth1 4710
Description: Equality of the first members of equal ordered pairs. (Contributed by NM, 28-May-2008.) (Revised by Mario Carneiro, 26-Apr-2015.)
Hypotheses
Ref Expression
opth1.1  |-  A  e. 
_V
opth1.2  |-  B  e. 
_V
Assertion
Ref Expression
opth1  |-  ( <. A ,  B >.  = 
<. C ,  D >.  ->  A  =  C )

Proof of Theorem opth1
StepHypRef Expression
1 opth1.1 . . . 4  |-  A  e. 
_V
21sneqr 4183 . . 3  |-  ( { A }  =  { C }  ->  A  =  C )
32a1i 11 . 2  |-  ( <. A ,  B >.  = 
<. C ,  D >.  -> 
( { A }  =  { C }  ->  A  =  C ) )
4 opth1.2 . . . . . . . . 9  |-  B  e. 
_V
51, 4opi1 4704 . . . . . . . 8  |-  { A }  e.  <. A ,  B >.
6 id 22 . . . . . . . 8  |-  ( <. A ,  B >.  = 
<. C ,  D >.  ->  <. A ,  B >.  = 
<. C ,  D >. )
75, 6syl5eleq 2548 . . . . . . 7  |-  ( <. A ,  B >.  = 
<. C ,  D >.  ->  { A }  e.  <. C ,  D >. )
8 oprcl 4228 . . . . . . 7  |-  ( { A }  e.  <. C ,  D >.  ->  ( C  e.  _V  /\  D  e.  _V ) )
97, 8syl 16 . . . . . 6  |-  ( <. A ,  B >.  = 
<. C ,  D >.  -> 
( C  e.  _V  /\  D  e.  _V )
)
109simpld 457 . . . . 5  |-  ( <. A ,  B >.  = 
<. C ,  D >.  ->  C  e.  _V )
11 prid1g 4122 . . . . 5  |-  ( C  e.  _V  ->  C  e.  { C ,  D } )
1210, 11syl 16 . . . 4  |-  ( <. A ,  B >.  = 
<. C ,  D >.  ->  C  e.  { C ,  D } )
13 eleq2 2527 . . . 4  |-  ( { A }  =  { C ,  D }  ->  ( C  e.  { A }  <->  C  e.  { C ,  D } ) )
1412, 13syl5ibrcom 222 . . 3  |-  ( <. A ,  B >.  = 
<. C ,  D >.  -> 
( { A }  =  { C ,  D }  ->  C  e.  { A } ) )
15 elsni 4041 . . . 4  |-  ( C  e.  { A }  ->  C  =  A )
1615eqcomd 2462 . . 3  |-  ( C  e.  { A }  ->  A  =  C )
1714, 16syl6 33 . 2  |-  ( <. A ,  B >.  = 
<. C ,  D >.  -> 
( { A }  =  { C ,  D }  ->  A  =  C ) )
18 dfopg 4201 . . . . 5  |-  ( ( C  e.  _V  /\  D  e.  _V )  -> 
<. C ,  D >.  =  { { C } ,  { C ,  D } } )
197, 8, 183syl 20 . . . 4  |-  ( <. A ,  B >.  = 
<. C ,  D >.  ->  <. C ,  D >.  =  { { C } ,  { C ,  D } } )
207, 19eleqtrd 2544 . . 3  |-  ( <. A ,  B >.  = 
<. C ,  D >.  ->  { A }  e.  { { C } ,  { C ,  D } } )
21 elpri 4036 . . 3  |-  ( { A }  e.  { { C } ,  { C ,  D } }  ->  ( { A }  =  { C }  \/  { A }  =  { C ,  D } ) )
2220, 21syl 16 . 2  |-  ( <. A ,  B >.  = 
<. C ,  D >.  -> 
( { A }  =  { C }  \/  { A }  =  { C ,  D }
) )
233, 17, 22mpjaod 379 1  |-  ( <. A ,  B >.  = 
<. C ,  D >.  ->  A  =  C )
Colors of variables: wff setvar class
Syntax hints:    -> wi 4    \/ wo 366    /\ wa 367    = wceq 1398    e. wcel 1823   _Vcvv 3106   {csn 4016   {cpr 4018   <.cop 4022
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1623  ax-4 1636  ax-5 1709  ax-6 1752  ax-7 1795  ax-9 1827  ax-10 1842  ax-11 1847  ax-12 1859  ax-13 2004  ax-ext 2432  ax-sep 4560  ax-nul 4568  ax-pr 4676
This theorem depends on definitions:  df-bi 185  df-or 368  df-an 369  df-3an 973  df-tru 1401  df-ex 1618  df-nf 1622  df-sb 1745  df-clab 2440  df-cleq 2446  df-clel 2449  df-nfc 2604  df-ne 2651  df-v 3108  df-dif 3464  df-un 3466  df-in 3468  df-ss 3475  df-nul 3784  df-if 3930  df-sn 4017  df-pr 4019  df-op 4023
This theorem is referenced by:  opth  4711  dmsnopg  5462  funcnvsn  5615  oprabid  6297  seqomlem2  7108  unxpdomlem3  7719  dfac5lem4  8498  dcomex  8818  canthwelem  9017  uzrdgfni  12051  gsum2d2  17198  2trllemA  24754  2pthon  24806  2pthon3v  24808  constr3lem2  24848
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