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Description: The supersets of a nonempty set which are also subsets of a given base set form a filter. (Contributed by Jeff Hankins, 12-Nov-2009) (Revised by Stefan O'Rear, 7-Aug-2015)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | supfil | |- ( ( A e. V /\ B C_ A /\ B =/= (/) ) -> { x e. ~P A | B C_ x } e. ( Fil ` A ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | sseq2 | |- ( x = y -> ( B C_ x <-> B C_ y ) ) |
|
| 2 | 1 | elrab | |- ( y e. { x e. ~P A | B C_ x } <-> ( y e. ~P A /\ B C_ y ) ) |
| 3 | velpw | |- ( y e. ~P A <-> y C_ A ) |
|
| 4 | 3 | anbi1i | |- ( ( y e. ~P A /\ B C_ y ) <-> ( y C_ A /\ B C_ y ) ) |
| 5 | 2 4 | bitri | |- ( y e. { x e. ~P A | B C_ x } <-> ( y C_ A /\ B C_ y ) ) |
| 6 | 5 | a1i | |- ( ( A e. V /\ B C_ A /\ B =/= (/) ) -> ( y e. { x e. ~P A | B C_ x } <-> ( y C_ A /\ B C_ y ) ) ) |
| 7 | simp1 | |- ( ( A e. V /\ B C_ A /\ B =/= (/) ) -> A e. V ) |
|
| 8 | simp2 | |- ( ( A e. V /\ B C_ A /\ B =/= (/) ) -> B C_ A ) |
|
| 9 | sseq2 | |- ( y = A -> ( B C_ y <-> B C_ A ) ) |
|
| 10 | 9 | sbcieg | |- ( A e. V -> ( [. A / y ]. B C_ y <-> B C_ A ) ) |
| 11 | 7 10 | syl | |- ( ( A e. V /\ B C_ A /\ B =/= (/) ) -> ( [. A / y ]. B C_ y <-> B C_ A ) ) |
| 12 | 8 11 | mpbird | |- ( ( A e. V /\ B C_ A /\ B =/= (/) ) -> [. A / y ]. B C_ y ) |
| 13 | ss0 | |- ( B C_ (/) -> B = (/) ) |
|
| 14 | 13 | necon3ai | |- ( B =/= (/) -> -. B C_ (/) ) |
| 15 | 14 | 3ad2ant3 | |- ( ( A e. V /\ B C_ A /\ B =/= (/) ) -> -. B C_ (/) ) |
| 16 | 0ex | |- (/) e. _V |
|
| 17 | sseq2 | |- ( y = (/) -> ( B C_ y <-> B C_ (/) ) ) |
|
| 18 | 16 17 | sbcie | |- ( [. (/) / y ]. B C_ y <-> B C_ (/) ) |
| 19 | 15 18 | sylnibr | |- ( ( A e. V /\ B C_ A /\ B =/= (/) ) -> -. [. (/) / y ]. B C_ y ) |
| 20 | sstr | |- ( ( B C_ w /\ w C_ z ) -> B C_ z ) |
|
| 21 | 20 | expcom | |- ( w C_ z -> ( B C_ w -> B C_ z ) ) |
| 22 | vex | |- w e. _V |
|
| 23 | sseq2 | |- ( y = w -> ( B C_ y <-> B C_ w ) ) |
|
| 24 | 22 23 | sbcie | |- ( [. w / y ]. B C_ y <-> B C_ w ) |
| 25 | vex | |- z e. _V |
|
| 26 | sseq2 | |- ( y = z -> ( B C_ y <-> B C_ z ) ) |
|
| 27 | 25 26 | sbcie | |- ( [. z / y ]. B C_ y <-> B C_ z ) |
| 28 | 21 24 27 | 3imtr4g | |- ( w C_ z -> ( [. w / y ]. B C_ y -> [. z / y ]. B C_ y ) ) |
| 29 | 28 | 3ad2ant3 | |- ( ( ( A e. V /\ B C_ A /\ B =/= (/) ) /\ z C_ A /\ w C_ z ) -> ( [. w / y ]. B C_ y -> [. z / y ]. B C_ y ) ) |
| 30 | ssin | |- ( ( B C_ z /\ B C_ w ) <-> B C_ ( z i^i w ) ) |
|
| 31 | 30 | biimpi | |- ( ( B C_ z /\ B C_ w ) -> B C_ ( z i^i w ) ) |
| 32 | 27 24 31 | syl2anb | |- ( ( [. z / y ]. B C_ y /\ [. w / y ]. B C_ y ) -> B C_ ( z i^i w ) ) |
| 33 | 25 | inex1 | |- ( z i^i w ) e. _V |
| 34 | sseq2 | |- ( y = ( z i^i w ) -> ( B C_ y <-> B C_ ( z i^i w ) ) ) |
|
| 35 | 33 34 | sbcie | |- ( [. ( z i^i w ) / y ]. B C_ y <-> B C_ ( z i^i w ) ) |
| 36 | 32 35 | sylibr | |- ( ( [. z / y ]. B C_ y /\ [. w / y ]. B C_ y ) -> [. ( z i^i w ) / y ]. B C_ y ) |
| 37 | 36 | a1i | |- ( ( ( A e. V /\ B C_ A /\ B =/= (/) ) /\ z C_ A /\ w C_ A ) -> ( ( [. z / y ]. B C_ y /\ [. w / y ]. B C_ y ) -> [. ( z i^i w ) / y ]. B C_ y ) ) |
| 38 | 6 7 12 19 29 37 | isfild | |- ( ( A e. V /\ B C_ A /\ B =/= (/) ) -> { x e. ~P A | B C_ x } e. ( Fil ` A ) ) |