Description: Ordinal zero maps to a surreal number. (Contributed by RP, 21-Sep-2023)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | 0no | |- (/) e. No |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | 0xp | |- ( (/) X. { 2o } ) = (/) |
|
| 2 | 0elon | |- (/) e. On |
|
| 3 | 2 | onnoi | |- ( (/) X. { 2o } ) e. No |
| 4 | 1 3 | eqeltrri | |- (/) e. No |