Description: Surreal exponentiation to zero. (Contributed by Scott Fenton, 24-Jul-2025)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | exps0 | |- ( A e. No -> ( A ^su 0s ) = 1s ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | 0zs | |- 0s e. ZZ_s | |
| 2 | expsval | |- ( ( A e. No /\ 0s e. ZZ_s ) -> ( A ^su 0s ) = if ( 0s = 0s , 1s , if ( 0s | |
| 3 | 1 2 | mpan2 | |- ( A e. No -> ( A ^su 0s ) = if ( 0s = 0s , 1s , if ( 0s | 
| 4 | eqid | |- 0s = 0s | |
| 5 | 4 | iftruei | |- if ( 0s = 0s , 1s , if ( 0s | 
| 6 | 3 5 | eqtrdi | |- ( A e. No -> ( A ^su 0s ) = 1s ) |