Description: A non-disjointness condition. (Contributed by Glauco Siliprandi, 17-Aug-2020)
Ref | Expression | ||
---|---|---|---|
Hypothesis | ndisj2.1 | |
|
Assertion | ndisj2 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ndisj2.1 | |
|
2 | 1 | disjor | |
3 | 2 | notbii | |
4 | rexnal | |
|
5 | rexnal | |
|
6 | ioran | |
|
7 | df-ne | |
|
8 | df-ne | |
|
9 | 7 8 | anbi12i | |
10 | 6 9 | bitr4i | |
11 | 10 | rexbii | |
12 | 5 11 | bitr3i | |
13 | 12 | rexbii | |
14 | 3 4 13 | 3bitr2i | |