Description: Theorem *2.24 of WhiteheadRussell p. 104. Its associated inference is pm2.24i . Commuted form of pm2.21 . (Contributed by NM, 3-Jan-2005)
Ref | Expression | ||
---|---|---|---|
Assertion | pm2.24 | |- ( ph -> ( -. ph -> ps ) ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | pm2.21 | |- ( -. ph -> ( ph -> ps ) ) |
|
2 | 1 | com12 | |- ( ph -> ( -. ph -> ps ) ) |