Description: A trichotomy law for ordinal classes. (Contributed by NM, 2-Nov-2003)
Ref | Expression | ||
---|---|---|---|
Assertion | ordtri2or2 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ordtri2or | |
|
2 | ordelss | |
|
3 | 2 | ex | |
4 | 3 | orim1d | |
5 | 4 | adantl | |
6 | 1 5 | mpd | |