Description: Inference commuting a nested conjunction in antecedent. (Contributed by NM, 24-May-2006) (Proof shortened by Wolf Lammen, 24-Nov-2012)
Ref | Expression | ||
---|---|---|---|
Hypothesis | an32s.1 | |- ( ( ( ph /\ ps ) /\ ch ) -> th ) |
|
Assertion | ancom1s | |- ( ( ( ps /\ ph ) /\ ch ) -> th ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | an32s.1 | |- ( ( ( ph /\ ps ) /\ ch ) -> th ) |
|
2 | pm3.22 | |- ( ( ps /\ ph ) -> ( ph /\ ps ) ) |
|
3 | 2 1 | sylan | |- ( ( ( ps /\ ph ) /\ ch ) -> th ) |