Description: Surreal one is a left identity element for multiplication. (Contributed by Scott Fenton, 14-Mar-2025)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | mulslidd.1 | |- ( ph -> A e. No ) | |
| Assertion | mulslidd | |- ( ph -> ( 1s x.s A ) = A ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | mulslidd.1 | |- ( ph -> A e. No ) | |
| 2 | mulslid | |- ( A e. No -> ( 1s x.s A ) = A ) | |
| 3 | 1 2 | syl | |- ( ph -> ( 1s x.s A ) = A ) |