Description: Simplification. Similar to Theorem *3.27 (Simp) of WhiteheadRussell p. 112. (Contributed by NM, 3-Jan-1993) (Proof shortened by Wolf Lammen, 13-Nov-2012)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | simprim | |- ( -. ( ph -> -. ps ) -> ps ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | idd | |- ( ph -> ( ps -> ps ) ) |
|
| 2 | 1 | impi | |- ( -. ( ph -> -. ps ) -> ps ) |