Description: 1 is not a limit ordinal. (Contributed by BTernaryTau, 1-Dec-2024) (Proof shortened by RP, 13-Dec-2024)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | nlim1NEW | |- -. Lim 1o |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | 0elon | |- (/) e. On |
|
| 2 | nlimsuc | |- ( (/) e. On -> -. Lim suc (/) ) |
|
| 3 | df-1o | |- 1o = suc (/) |
|
| 4 | limeq | |- ( 1o = suc (/) -> ( Lim 1o <-> Lim suc (/) ) ) |
|
| 5 | 3 4 | ax-mp | |- ( Lim 1o <-> Lim suc (/) ) |
| 6 | 2 5 | sylnibr | |- ( (/) e. On -> -. Lim 1o ) |
| 7 | 1 6 | ax-mp | |- -. Lim 1o |