Description: A filter contains the neighborhood filter as a subfilter. (Contributed by Mario Carneiro, 9-Apr-2015) (Revised by Stefan O'Rear, 9-Aug-2015)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | flimneiss | |- ( A e. ( J fLim F ) -> ( ( nei ` J ) ` { A } ) C_ F ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | eqid | |- U. J = U. J | |
| 2 | 1 | elflim2 |  |-  ( A e. ( J fLim F ) <-> ( ( J e. Top /\ F e. U. ran Fil /\ F C_ ~P U. J ) /\ ( A e. U. J /\ ( ( nei ` J ) ` { A } ) C_ F ) ) ) | 
| 3 | 2 | simprbi |  |-  ( A e. ( J fLim F ) -> ( A e. U. J /\ ( ( nei ` J ) ` { A } ) C_ F ) ) | 
| 4 | 3 | simprd |  |-  ( A e. ( J fLim F ) -> ( ( nei ` J ) ` { A } ) C_ F ) |