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Theorem foeqcnvco 6213
Description: Condition for function equality in terms of vanishing of the composition with the converse. EDITORIAL: Is there a relation-algebraic proof of this? (Contributed by Stefan O'Rear, 12-Feb-2015.)
Assertion
Ref Expression
foeqcnvco  |-  ( ( F : A -onto-> B  /\  G : A -onto-> B
)  ->  ( F  =  G  <->  ( F  o.  `' G )  =  (  _I  |`  B )
) )

Proof of Theorem foeqcnvco
Dummy variables  x  y are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 fococnv2 5856 . . . 4  |-  ( F : A -onto-> B  -> 
( F  o.  `' F )  =  (  _I  |`  B )
)
2 cnveq 5028 . . . . . 6  |-  ( F  =  G  ->  `' F  =  `' G
)
32coeq2d 5017 . . . . 5  |-  ( F  =  G  ->  ( F  o.  `' F
)  =  ( F  o.  `' G ) )
43eqeq1d 2431 . . . 4  |-  ( F  =  G  ->  (
( F  o.  `' F )  =  (  _I  |`  B )  <->  ( F  o.  `' G
)  =  (  _I  |`  B ) ) )
51, 4syl5ibcom 223 . . 3  |-  ( F : A -onto-> B  -> 
( F  =  G  ->  ( F  o.  `' G )  =  (  _I  |`  B )
) )
65adantr 466 . 2  |-  ( ( F : A -onto-> B  /\  G : A -onto-> B
)  ->  ( F  =  G  ->  ( F  o.  `' G )  =  (  _I  |`  B ) ) )
7 fofn 5812 . . . . 5  |-  ( F : A -onto-> B  ->  F  Fn  A )
87ad2antrr 730 . . . 4  |-  ( ( ( F : A -onto-> B  /\  G : A -onto-> B )  /\  ( F  o.  `' G
)  =  (  _I  |`  B ) )  ->  F  Fn  A )
9 fofn 5812 . . . . 5  |-  ( G : A -onto-> B  ->  G  Fn  A )
109ad2antlr 731 . . . 4  |-  ( ( ( F : A -onto-> B  /\  G : A -onto-> B )  /\  ( F  o.  `' G
)  =  (  _I  |`  B ) )  ->  G  Fn  A )
119adantl 467 . . . . . . . . . . . 12  |-  ( ( F : A -onto-> B  /\  G : A -onto-> B
)  ->  G  Fn  A )
12 fnopfv 6029 . . . . . . . . . . . 12  |-  ( ( G  Fn  A  /\  x  e.  A )  -> 
<. x ,  ( G `
 x ) >.  e.  G )
1311, 12sylan 473 . . . . . . . . . . 11  |-  ( ( ( F : A -onto-> B  /\  G : A -onto-> B )  /\  x  e.  A )  ->  <. x ,  ( G `  x ) >.  e.  G
)
14 fvex 5891 . . . . . . . . . . . . 13  |-  ( G `
 x )  e. 
_V
15 vex 3090 . . . . . . . . . . . . 13  |-  x  e. 
_V
1614, 15brcnv 5037 . . . . . . . . . . . 12  |-  ( ( G `  x ) `' G x  <->  x G
( G `  x
) )
17 df-br 4427 . . . . . . . . . . . 12  |-  ( x G ( G `  x )  <->  <. x ,  ( G `  x
) >.  e.  G )
1816, 17bitri 252 . . . . . . . . . . 11  |-  ( ( G `  x ) `' G x  <->  <. x ,  ( G `  x
) >.  e.  G )
1913, 18sylibr 215 . . . . . . . . . 10  |-  ( ( ( F : A -onto-> B  /\  G : A -onto-> B )  /\  x  e.  A )  ->  ( G `  x ) `' G x )
207adantr 466 . . . . . . . . . . . 12  |-  ( ( F : A -onto-> B  /\  G : A -onto-> B
)  ->  F  Fn  A )
21 fnopfv 6029 . . . . . . . . . . . 12  |-  ( ( F  Fn  A  /\  x  e.  A )  -> 
<. x ,  ( F `
 x ) >.  e.  F )
2220, 21sylan 473 . . . . . . . . . . 11  |-  ( ( ( F : A -onto-> B  /\  G : A -onto-> B )  /\  x  e.  A )  ->  <. x ,  ( F `  x ) >.  e.  F
)
23 df-br 4427 . . . . . . . . . . 11  |-  ( x F ( F `  x )  <->  <. x ,  ( F `  x
) >.  e.  F )
2422, 23sylibr 215 . . . . . . . . . 10  |-  ( ( ( F : A -onto-> B  /\  G : A -onto-> B )  /\  x  e.  A )  ->  x F ( F `  x ) )
25 breq2 4430 . . . . . . . . . . . 12  |-  ( y  =  x  ->  (
( G `  x
) `' G y  <-> 
( G `  x
) `' G x ) )
26 breq1 4429 . . . . . . . . . . . 12  |-  ( y  =  x  ->  (
y F ( F `
 x )  <->  x F
( F `  x
) ) )
2725, 26anbi12d 715 . . . . . . . . . . 11  |-  ( y  =  x  ->  (
( ( G `  x ) `' G
y  /\  y F
( F `  x
) )  <->  ( ( G `  x ) `' G x  /\  x F ( F `  x ) ) ) )
2815, 27spcev 3179 . . . . . . . . . 10  |-  ( ( ( G `  x
) `' G x  /\  x F ( F `  x ) )  ->  E. y
( ( G `  x ) `' G
y  /\  y F
( F `  x
) ) )
2919, 24, 28syl2anc 665 . . . . . . . . 9  |-  ( ( ( F : A -onto-> B  /\  G : A -onto-> B )  /\  x  e.  A )  ->  E. y
( ( G `  x ) `' G
y  /\  y F
( F `  x
) ) )
30 fvex 5891 . . . . . . . . . 10  |-  ( F `
 x )  e. 
_V
3114, 30brco 5025 . . . . . . . . 9  |-  ( ( G `  x ) ( F  o.  `' G ) ( F `
 x )  <->  E. y
( ( G `  x ) `' G
y  /\  y F
( F `  x
) ) )
3229, 31sylibr 215 . . . . . . . 8  |-  ( ( ( F : A -onto-> B  /\  G : A -onto-> B )  /\  x  e.  A )  ->  ( G `  x )
( F  o.  `' G ) ( F `
 x ) )
3332adantlr 719 . . . . . . 7  |-  ( ( ( ( F : A -onto-> B  /\  G : A -onto-> B )  /\  ( F  o.  `' G
)  =  (  _I  |`  B ) )  /\  x  e.  A )  ->  ( G `  x
) ( F  o.  `' G ) ( F `
 x ) )
34 breq 4428 . . . . . . . 8  |-  ( ( F  o.  `' G
)  =  (  _I  |`  B )  ->  (
( G `  x
) ( F  o.  `' G ) ( F `
 x )  <->  ( G `  x ) (  _I  |`  B ) ( F `
 x ) ) )
3534ad2antlr 731 . . . . . . 7  |-  ( ( ( ( F : A -onto-> B  /\  G : A -onto-> B )  /\  ( F  o.  `' G
)  =  (  _I  |`  B ) )  /\  x  e.  A )  ->  ( ( G `  x ) ( F  o.  `' G ) ( F `  x
)  <->  ( G `  x ) (  _I  |`  B ) ( F `
 x ) ) )
3633, 35mpbid 213 . . . . . 6  |-  ( ( ( ( F : A -onto-> B  /\  G : A -onto-> B )  /\  ( F  o.  `' G
)  =  (  _I  |`  B ) )  /\  x  e.  A )  ->  ( G `  x
) (  _I  |`  B ) ( F `  x
) )
37 fof 5810 . . . . . . . . . 10  |-  ( G : A -onto-> B  ->  G : A --> B )
3837adantl 467 . . . . . . . . 9  |-  ( ( F : A -onto-> B  /\  G : A -onto-> B
)  ->  G : A
--> B )
3938ffvelrnda 6037 . . . . . . . 8  |-  ( ( ( F : A -onto-> B  /\  G : A -onto-> B )  /\  x  e.  A )  ->  ( G `  x )  e.  B )
40 fof 5810 . . . . . . . . . 10  |-  ( F : A -onto-> B  ->  F : A --> B )
4140adantr 466 . . . . . . . . 9  |-  ( ( F : A -onto-> B  /\  G : A -onto-> B
)  ->  F : A
--> B )
4241ffvelrnda 6037 . . . . . . . 8  |-  ( ( ( F : A -onto-> B  /\  G : A -onto-> B )  /\  x  e.  A )  ->  ( F `  x )  e.  B )
43 resieq 5135 . . . . . . . 8  |-  ( ( ( G `  x
)  e.  B  /\  ( F `  x )  e.  B )  -> 
( ( G `  x ) (  _I  |`  B ) ( F `
 x )  <->  ( G `  x )  =  ( F `  x ) ) )
4439, 42, 43syl2anc 665 . . . . . . 7  |-  ( ( ( F : A -onto-> B  /\  G : A -onto-> B )  /\  x  e.  A )  ->  (
( G `  x
) (  _I  |`  B ) ( F `  x
)  <->  ( G `  x )  =  ( F `  x ) ) )
4544adantlr 719 . . . . . 6  |-  ( ( ( ( F : A -onto-> B  /\  G : A -onto-> B )  /\  ( F  o.  `' G
)  =  (  _I  |`  B ) )  /\  x  e.  A )  ->  ( ( G `  x ) (  _I  |`  B ) ( F `
 x )  <->  ( G `  x )  =  ( F `  x ) ) )
4636, 45mpbid 213 . . . . 5  |-  ( ( ( ( F : A -onto-> B  /\  G : A -onto-> B )  /\  ( F  o.  `' G
)  =  (  _I  |`  B ) )  /\  x  e.  A )  ->  ( G `  x
)  =  ( F `
 x ) )
4746eqcomd 2437 . . . 4  |-  ( ( ( ( F : A -onto-> B  /\  G : A -onto-> B )  /\  ( F  o.  `' G
)  =  (  _I  |`  B ) )  /\  x  e.  A )  ->  ( F `  x
)  =  ( G `
 x ) )
488, 10, 47eqfnfvd 5994 . . 3  |-  ( ( ( F : A -onto-> B  /\  G : A -onto-> B )  /\  ( F  o.  `' G
)  =  (  _I  |`  B ) )  ->  F  =  G )
4948ex 435 . 2  |-  ( ( F : A -onto-> B  /\  G : A -onto-> B
)  ->  ( ( F  o.  `' G
)  =  (  _I  |`  B )  ->  F  =  G ) )
506, 49impbid 193 1  |-  ( ( F : A -onto-> B  /\  G : A -onto-> B
)  ->  ( F  =  G  <->  ( F  o.  `' G )  =  (  _I  |`  B )
) )
Colors of variables: wff setvar class
Syntax hints:    -> wi 4    <-> wb 187    /\ wa 370    = wceq 1437   E.wex 1659    e. wcel 1870   <.cop 4008   class class class wbr 4426    _I cid 4764   `'ccnv 4853    |` cres 4856    o. ccom 4858    Fn wfn 5596   -->wf 5597   -onto->wfo 5599   ` cfv 5601
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1665  ax-4 1678  ax-5 1751  ax-6 1797  ax-7 1841  ax-8 1872  ax-9 1874  ax-10 1889  ax-11 1894  ax-12 1907  ax-13 2055  ax-ext 2407  ax-sep 4548  ax-nul 4556  ax-pow 4603  ax-pr 4661
This theorem depends on definitions:  df-bi 188  df-or 371  df-an 372  df-3an 984  df-tru 1440  df-ex 1660  df-nf 1664  df-sb 1790  df-eu 2270  df-mo 2271  df-clab 2415  df-cleq 2421  df-clel 2424  df-nfc 2579  df-ne 2627  df-ral 2787  df-rex 2788  df-rab 2791  df-v 3089  df-sbc 3306  df-csb 3402  df-dif 3445  df-un 3447  df-in 3449  df-ss 3456  df-nul 3768  df-if 3916  df-sn 4003  df-pr 4005  df-op 4009  df-uni 4223  df-br 4427  df-opab 4485  df-mpt 4486  df-id 4769  df-xp 4860  df-rel 4861  df-cnv 4862  df-co 4863  df-dm 4864  df-rn 4865  df-res 4866  df-ima 4867  df-iota 5565  df-fun 5603  df-fn 5604  df-f 5605  df-fo 5607  df-fv 5609
This theorem is referenced by: (None)
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