Description: An ordinal is a subset of another ordinal if and only if it belongs to its successor. (Contributed by NM, 28-Nov-2003)
Ref | Expression | ||
---|---|---|---|
Assertion | ordsssuc | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | eloni | |
|
2 | ordsseleq | |
|
3 | 1 2 | sylan | |
4 | elsucg | |
|
5 | 4 | adantr | |
6 | 3 5 | bitr4d | |