Description: The non-negative surreal integers are a subset of the old set of _om . (Contributed by Scott Fenton, 18-Apr-2025)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | n0ssold | |- NN0_s C_ ( _Old ` _om ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | omex | |- _om e. _V |
|
| 2 | n0ssoldg | |- ( _om e. _V -> NN0_s C_ ( _Old ` _om ) ) |
|
| 3 | 1 2 | ax-mp | |- NN0_s C_ ( _Old ` _om ) |