Description: An ordinal number is an ordinal class. (Contributed by NM, 11-Jun-1994)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | on.1 | |- A e. On |
|
| Assertion | onordi | |- Ord A |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | on.1 | |- A e. On |
|
| 2 | eloni | |- ( A e. On -> Ord A ) |
|
| 3 | 1 2 | ax-mp | |- Ord A |