Description: Simplification of triple conjunction. (Contributed by NM, 9-Nov-2011)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | simp1l | |- ( ( ( ph /\ ps ) /\ ch /\ th ) -> ph ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | simpl | |- ( ( ph /\ ps ) -> ph ) |
|
| 2 | 1 | 3ad2ant1 | |- ( ( ( ph /\ ps ) /\ ch /\ th ) -> ph ) |