Description: The ordinal Hausdorff spaces are 1o and 2o . (Contributed by Chen-Pang He, 10-Nov-2015)
Ref | Expression | ||
---|---|---|---|
Assertion | oninhaus |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | haust1 | ||
2 | 1 | ssriv | |
3 | sslin | ||
4 | 2 3 | ax-mp | |
5 | onint1 | ||
6 | 4 5 | sseqtri | |
7 | ssoninhaus | ||
8 | 6 7 | eqssi |