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Description: A utility theorem for proving equivalence of "is a functor". (Contributed by Zhi Wang, 1-Oct-2024)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | funcf2lem | |- ( G e. X_ z e. ( B X. B ) ( ( ( F ` ( 1st ` z ) ) J ( F ` ( 2nd ` z ) ) ) ^m ( H ` z ) ) <-> ( G e. _V /\ G Fn ( B X. B ) /\ A. x e. B A. y e. B ( x G y ) : ( x H y ) --> ( ( F ` x ) J ( F ` y ) ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | elixp2 | |- ( G e. X_ z e. ( B X. B ) ( ( ( F ` ( 1st ` z ) ) J ( F ` ( 2nd ` z ) ) ) ^m ( H ` z ) ) <-> ( G e. _V /\ G Fn ( B X. B ) /\ A. z e. ( B X. B ) ( G ` z ) e. ( ( ( F ` ( 1st ` z ) ) J ( F ` ( 2nd ` z ) ) ) ^m ( H ` z ) ) ) ) |
|
| 2 | fveq2 | |- ( z = <. x , y >. -> ( G ` z ) = ( G ` <. x , y >. ) ) |
|
| 3 | df-ov | |- ( x G y ) = ( G ` <. x , y >. ) |
|
| 4 | 2 3 | eqtr4di | |- ( z = <. x , y >. -> ( G ` z ) = ( x G y ) ) |
| 5 | vex | |- x e. _V |
|
| 6 | vex | |- y e. _V |
|
| 7 | 5 6 | op1std | |- ( z = <. x , y >. -> ( 1st ` z ) = x ) |
| 8 | 7 | fveq2d | |- ( z = <. x , y >. -> ( F ` ( 1st ` z ) ) = ( F ` x ) ) |
| 9 | 5 6 | op2ndd | |- ( z = <. x , y >. -> ( 2nd ` z ) = y ) |
| 10 | 9 | fveq2d | |- ( z = <. x , y >. -> ( F ` ( 2nd ` z ) ) = ( F ` y ) ) |
| 11 | 8 10 | oveq12d | |- ( z = <. x , y >. -> ( ( F ` ( 1st ` z ) ) J ( F ` ( 2nd ` z ) ) ) = ( ( F ` x ) J ( F ` y ) ) ) |
| 12 | fveq2 | |- ( z = <. x , y >. -> ( H ` z ) = ( H ` <. x , y >. ) ) |
|
| 13 | df-ov | |- ( x H y ) = ( H ` <. x , y >. ) |
|
| 14 | 12 13 | eqtr4di | |- ( z = <. x , y >. -> ( H ` z ) = ( x H y ) ) |
| 15 | 11 14 | oveq12d | |- ( z = <. x , y >. -> ( ( ( F ` ( 1st ` z ) ) J ( F ` ( 2nd ` z ) ) ) ^m ( H ` z ) ) = ( ( ( F ` x ) J ( F ` y ) ) ^m ( x H y ) ) ) |
| 16 | 4 15 | eleq12d | |- ( z = <. x , y >. -> ( ( G ` z ) e. ( ( ( F ` ( 1st ` z ) ) J ( F ` ( 2nd ` z ) ) ) ^m ( H ` z ) ) <-> ( x G y ) e. ( ( ( F ` x ) J ( F ` y ) ) ^m ( x H y ) ) ) ) |
| 17 | ovex | |- ( ( F ` x ) J ( F ` y ) ) e. _V |
|
| 18 | ovex | |- ( x H y ) e. _V |
|
| 19 | 17 18 | elmap | |- ( ( x G y ) e. ( ( ( F ` x ) J ( F ` y ) ) ^m ( x H y ) ) <-> ( x G y ) : ( x H y ) --> ( ( F ` x ) J ( F ` y ) ) ) |
| 20 | 16 19 | bitrdi | |- ( z = <. x , y >. -> ( ( G ` z ) e. ( ( ( F ` ( 1st ` z ) ) J ( F ` ( 2nd ` z ) ) ) ^m ( H ` z ) ) <-> ( x G y ) : ( x H y ) --> ( ( F ` x ) J ( F ` y ) ) ) ) |
| 21 | 20 | ralxp | |- ( A. z e. ( B X. B ) ( G ` z ) e. ( ( ( F ` ( 1st ` z ) ) J ( F ` ( 2nd ` z ) ) ) ^m ( H ` z ) ) <-> A. x e. B A. y e. B ( x G y ) : ( x H y ) --> ( ( F ` x ) J ( F ` y ) ) ) |
| 22 | 21 | 3anbi3i | |- ( ( G e. _V /\ G Fn ( B X. B ) /\ A. z e. ( B X. B ) ( G ` z ) e. ( ( ( F ` ( 1st ` z ) ) J ( F ` ( 2nd ` z ) ) ) ^m ( H ` z ) ) ) <-> ( G e. _V /\ G Fn ( B X. B ) /\ A. x e. B A. y e. B ( x G y ) : ( x H y ) --> ( ( F ` x ) J ( F ` y ) ) ) ) |
| 23 | 1 22 | bitri | |- ( G e. X_ z e. ( B X. B ) ( ( ( F ` ( 1st ` z ) ) J ( F ` ( 2nd ` z ) ) ) ^m ( H ` z ) ) <-> ( G e. _V /\ G Fn ( B X. B ) /\ A. x e. B A. y e. B ( x G y ) : ( x H y ) --> ( ( F ` x ) J ( F ` y ) ) ) ) |