Description: If something is true for an open neighborhood, it must be true for a neighborhood. (Contributed by Zhi Wang, 31-Aug-2024)
Ref | Expression | ||
---|---|---|---|
Hypothesis | opnneir.1 | |
|
Assertion | opnneir | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | opnneir.1 | |
|
2 | anass | |
|
3 | opnneiss | |
|
4 | 3 | 3expib | |
5 | 4 | anim1d | |
6 | 2 5 | biimtrrid | |
7 | 6 | reximdv2 | |
8 | 1 7 | syl | |