Description: Obsolete version of peano3 as of 10-Jun-2026. (Contributed by NM, 3-Sep-2003) (Proof modification is discouraged.) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | peano3OLD | |- ( A e. _om -> suc A =/= (/) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | nsuceq0 | |- suc A =/= (/) |
|
| 2 | 1 | a1i | |- ( A e. _om -> suc A =/= (/) ) |