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Description: Theorem *5.31 of WhiteheadRussell p. 125. (Contributed by NM, 3-Jan-2005)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | pm5.31 | |- ( ( ch /\ ( ph -> ps ) ) -> ( ph -> ( ps /\ ch ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | simpr | |- ( ( ch /\ ( ph -> ps ) ) -> ( ph -> ps ) ) |
|
| 2 | simpl | |- ( ( ch /\ ( ph -> ps ) ) -> ch ) |
|
| 3 | 1 2 | jctird | |- ( ( ch /\ ( ph -> ps ) ) -> ( ph -> ( ps /\ ch ) ) ) |