Description: Value of the morphism part of the identity functor. (Contributed by Mario Carneiro, 28-Jan-2017)
Ref | Expression | ||
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Hypotheses | idfuval.i | |- I = ( idFunc ` C ) |
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idfuval.b | |- B = ( Base ` C ) |
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idfuval.c | |- ( ph -> C e. Cat ) |
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idfuval.h | |- H = ( Hom ` C ) |
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idfu2nd.x | |- ( ph -> X e. B ) |
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idfu2nd.y | |- ( ph -> Y e. B ) |
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idfu2.f | |- ( ph -> F e. ( X H Y ) ) |
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Assertion | idfu2 | |- ( ph -> ( ( X ( 2nd ` I ) Y ) ` F ) = F ) |
Step | Hyp | Ref | Expression |
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1 | idfuval.i | |- I = ( idFunc ` C ) |
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2 | idfuval.b | |- B = ( Base ` C ) |
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3 | idfuval.c | |- ( ph -> C e. Cat ) |
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4 | idfuval.h | |- H = ( Hom ` C ) |
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5 | idfu2nd.x | |- ( ph -> X e. B ) |
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6 | idfu2nd.y | |- ( ph -> Y e. B ) |
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7 | idfu2.f | |- ( ph -> F e. ( X H Y ) ) |
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8 | 1 2 3 4 5 6 | idfu2nd | |- ( ph -> ( X ( 2nd ` I ) Y ) = ( _I |` ( X H Y ) ) ) |
9 | 8 | fveq1d | |- ( ph -> ( ( X ( 2nd ` I ) Y ) ` F ) = ( ( _I |` ( X H Y ) ) ` F ) ) |
10 | fvresi | |- ( F e. ( X H Y ) -> ( ( _I |` ( X H Y ) ) ` F ) = F ) |
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11 | 7 10 | syl | |- ( ph -> ( ( _I |` ( X H Y ) ) ` F ) = F ) |
12 | 9 11 | eqtrd | |- ( ph -> ( ( X ( 2nd ` I ) Y ) ` F ) = F ) |