Description: The intersection of a class of ordinal numbers exists iff it is an ordinal number. (Contributed by NM, 6-Nov-2003)
Ref | Expression | ||
---|---|---|---|
Assertion | onintrab | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | intex | |
|
2 | ssrab2 | |
|
3 | oninton | |
|
4 | 2 3 | mpan | |
5 | 1 4 | sylbir | |
6 | elex | |
|
7 | 5 6 | impbii | |