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Description: The predicate "is a filter." (Contributed by FL, 20-Jul-2007) (Revised by Mario Carneiro, 28-Jul-2015)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | isfil | |- ( F e. ( Fil ` X ) <-> ( F e. ( fBas ` X ) /\ A. x e. ~P X ( ( F i^i ~P x ) =/= (/) -> x e. F ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | df-fil | |- Fil = ( z e. _V |-> { f e. ( fBas ` z ) | A. x e. ~P z ( ( f i^i ~P x ) =/= (/) -> x e. f ) } ) |
|
| 2 | pweq | |- ( z = X -> ~P z = ~P X ) |
|
| 3 | 2 | adantr | |- ( ( z = X /\ f = F ) -> ~P z = ~P X ) |
| 4 | ineq1 | |- ( f = F -> ( f i^i ~P x ) = ( F i^i ~P x ) ) |
|
| 5 | 4 | neeq1d | |- ( f = F -> ( ( f i^i ~P x ) =/= (/) <-> ( F i^i ~P x ) =/= (/) ) ) |
| 6 | eleq2 | |- ( f = F -> ( x e. f <-> x e. F ) ) |
|
| 7 | 5 6 | imbi12d | |- ( f = F -> ( ( ( f i^i ~P x ) =/= (/) -> x e. f ) <-> ( ( F i^i ~P x ) =/= (/) -> x e. F ) ) ) |
| 8 | 7 | adantl | |- ( ( z = X /\ f = F ) -> ( ( ( f i^i ~P x ) =/= (/) -> x e. f ) <-> ( ( F i^i ~P x ) =/= (/) -> x e. F ) ) ) |
| 9 | 3 8 | raleqbidv | |- ( ( z = X /\ f = F ) -> ( A. x e. ~P z ( ( f i^i ~P x ) =/= (/) -> x e. f ) <-> A. x e. ~P X ( ( F i^i ~P x ) =/= (/) -> x e. F ) ) ) |
| 10 | fveq2 | |- ( z = X -> ( fBas ` z ) = ( fBas ` X ) ) |
|
| 11 | fvex | |- ( fBas ` z ) e. _V |
|
| 12 | elfvdm | |- ( F e. ( fBas ` X ) -> X e. dom fBas ) |
|
| 13 | 1 9 10 11 12 | elmptrab2 | |- ( F e. ( Fil ` X ) <-> ( F e. ( fBas ` X ) /\ A. x e. ~P X ( ( F i^i ~P x ) =/= (/) -> x e. F ) ) ) |