Description: Alternate proof of 0sdom1dom , shorter but requiring ax-un . (Contributed by NM, 28-Sep-2004) (Proof modification is discouraged.) (New usage is discouraged.)
Ref | Expression | ||
---|---|---|---|
Assertion | 0sdom1domALT |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | peano1 | ||
2 | sucdom | ||
3 | 1 2 | ax-mp | |
4 | df-1o | ||
5 | 4 | breq1i | |
6 | 3 5 | bitr4i |