Description: Simplification of doubly triple conjunction. (Contributed by NM, 17-Nov-2011)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | simp21 | |- ( ( ph /\ ( ps /\ ch /\ th ) /\ ta ) -> ps ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | simp1 | |- ( ( ps /\ ch /\ th ) -> ps ) |
|
| 2 | 1 | 3ad2ant2 | |- ( ( ph /\ ( ps /\ ch /\ th ) /\ ta ) -> ps ) |