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Description: The binary relation of a function value which is an ordered-pair class abstraction of a restricted binary relation is the restricted binary relation. The first hypothesis can often be obtained by using fvmptopab . (Contributed by AV, 29-Oct-2021)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | brfvopabrbr.1 | |- ( A ` Z ) = { <. x , y >. | ( x ( B ` Z ) y /\ ph ) } |
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| brfvopabrbr.2 | |- ( ( x = X /\ y = Y ) -> ( ph <-> ps ) ) |
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| brfvopabrbr.3 | |- Rel ( B ` Z ) |
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| Assertion | brfvopabrbr | |- ( X ( A ` Z ) Y <-> ( X ( B ` Z ) Y /\ ps ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | brfvopabrbr.1 | |- ( A ` Z ) = { <. x , y >. | ( x ( B ` Z ) y /\ ph ) } |
|
| 2 | brfvopabrbr.2 | |- ( ( x = X /\ y = Y ) -> ( ph <-> ps ) ) |
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| 3 | brfvopabrbr.3 | |- Rel ( B ` Z ) |
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| 4 | brne0 | |- ( X ( A ` Z ) Y -> ( A ` Z ) =/= (/) ) |
|
| 5 | fvprc | |- ( -. Z e. _V -> ( A ` Z ) = (/) ) |
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| 6 | 5 | necon1ai | |- ( ( A ` Z ) =/= (/) -> Z e. _V ) |
| 7 | 4 6 | syl | |- ( X ( A ` Z ) Y -> Z e. _V ) |
| 8 | 1 | relopabiv | |- Rel ( A ` Z ) |
| 9 | 8 | brrelex1i | |- ( X ( A ` Z ) Y -> X e. _V ) |
| 10 | 8 | brrelex2i | |- ( X ( A ` Z ) Y -> Y e. _V ) |
| 11 | 7 9 10 | 3jca | |- ( X ( A ` Z ) Y -> ( Z e. _V /\ X e. _V /\ Y e. _V ) ) |
| 12 | brne0 | |- ( X ( B ` Z ) Y -> ( B ` Z ) =/= (/) ) |
|
| 13 | fvprc | |- ( -. Z e. _V -> ( B ` Z ) = (/) ) |
|
| 14 | 13 | necon1ai | |- ( ( B ` Z ) =/= (/) -> Z e. _V ) |
| 15 | 12 14 | syl | |- ( X ( B ` Z ) Y -> Z e. _V ) |
| 16 | 3 | brrelex1i | |- ( X ( B ` Z ) Y -> X e. _V ) |
| 17 | 3 | brrelex2i | |- ( X ( B ` Z ) Y -> Y e. _V ) |
| 18 | 15 16 17 | 3jca | |- ( X ( B ` Z ) Y -> ( Z e. _V /\ X e. _V /\ Y e. _V ) ) |
| 19 | 18 | adantr | |- ( ( X ( B ` Z ) Y /\ ps ) -> ( Z e. _V /\ X e. _V /\ Y e. _V ) ) |
| 20 | 1 | a1i | |- ( Z e. _V -> ( A ` Z ) = { <. x , y >. | ( x ( B ` Z ) y /\ ph ) } ) |
| 21 | 20 2 | rbropap | |- ( ( Z e. _V /\ X e. _V /\ Y e. _V ) -> ( X ( A ` Z ) Y <-> ( X ( B ` Z ) Y /\ ps ) ) ) |
| 22 | 11 19 21 | pm5.21nii | |- ( X ( A ` Z ) Y <-> ( X ( B ` Z ) Y /\ ps ) ) |