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Description: The image of an isomorphism under a functor is an isomorphism. Proposition 3.21 of Adamek p. 32. (Contributed by Mario Carneiro, 3-Jan-2017)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | funciso.b | |- B = ( Base ` D ) |
|
| funciso.s | |- I = ( Iso ` D ) |
||
| funciso.t | |- J = ( Iso ` E ) |
||
| funciso.f | |- ( ph -> F ( D Func E ) G ) |
||
| funciso.x | |- ( ph -> X e. B ) |
||
| funciso.y | |- ( ph -> Y e. B ) |
||
| funciso.m | |- ( ph -> M e. ( X I Y ) ) |
||
| Assertion | funciso | |- ( ph -> ( ( X G Y ) ` M ) e. ( ( F ` X ) J ( F ` Y ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | funciso.b | |- B = ( Base ` D ) |
|
| 2 | funciso.s | |- I = ( Iso ` D ) |
|
| 3 | funciso.t | |- J = ( Iso ` E ) |
|
| 4 | funciso.f | |- ( ph -> F ( D Func E ) G ) |
|
| 5 | funciso.x | |- ( ph -> X e. B ) |
|
| 6 | funciso.y | |- ( ph -> Y e. B ) |
|
| 7 | funciso.m | |- ( ph -> M e. ( X I Y ) ) |
|
| 8 | eqid | |- ( Base ` E ) = ( Base ` E ) |
|
| 9 | eqid | |- ( Inv ` E ) = ( Inv ` E ) |
|
| 10 | df-br | |- ( F ( D Func E ) G <-> <. F , G >. e. ( D Func E ) ) |
|
| 11 | 4 10 | sylib | |- ( ph -> <. F , G >. e. ( D Func E ) ) |
| 12 | funcrcl | |- ( <. F , G >. e. ( D Func E ) -> ( D e. Cat /\ E e. Cat ) ) |
|
| 13 | 11 12 | syl | |- ( ph -> ( D e. Cat /\ E e. Cat ) ) |
| 14 | 13 | simprd | |- ( ph -> E e. Cat ) |
| 15 | 1 8 4 | funcf1 | |- ( ph -> F : B --> ( Base ` E ) ) |
| 16 | 15 5 | ffvelcdmd | |- ( ph -> ( F ` X ) e. ( Base ` E ) ) |
| 17 | 15 6 | ffvelcdmd | |- ( ph -> ( F ` Y ) e. ( Base ` E ) ) |
| 18 | eqid | |- ( Inv ` D ) = ( Inv ` D ) |
|
| 19 | 13 | simpld | |- ( ph -> D e. Cat ) |
| 20 | 1 2 18 19 5 6 7 | invisoinvr | |- ( ph -> M ( X ( Inv ` D ) Y ) ( ( X ( Inv ` D ) Y ) ` M ) ) |
| 21 | 1 18 9 4 5 6 20 | funcinv | |- ( ph -> ( ( X G Y ) ` M ) ( ( F ` X ) ( Inv ` E ) ( F ` Y ) ) ( ( Y G X ) ` ( ( X ( Inv ` D ) Y ) ` M ) ) ) |
| 22 | 8 9 14 16 17 3 21 | inviso1 | |- ( ph -> ( ( X G Y ) ` M ) e. ( ( F ` X ) J ( F ` Y ) ) ) |