Description: Ordinal 1 is strictly dominated by ordinal 2. (Contributed by NM, 4-Apr-2007)
Ref | Expression | ||
---|---|---|---|
Assertion | 1sdom2 | |- 1o ~< 2o |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 1onn | |- 1o e. _om |
|
2 | php4 | |- ( 1o e. _om -> 1o ~< suc 1o ) |
|
3 | 1 2 | ax-mp | |- 1o ~< suc 1o |
4 | df-2o | |- 2o = suc 1o |
|
5 | 3 4 | breqtrri | |- 1o ~< 2o |