Description: Simplification of conjunction. (Contributed by NM, 9-Mar-2012) (Proof shortened by Wolf Lammen, 23-Jun-2022)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | simpl1l | |- ( ( ( ( ph /\ ps ) /\ ch /\ th ) /\ ta ) -> ph ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | simpll | |- ( ( ( ph /\ ps ) /\ ta ) -> ph ) |
|
| 2 | 1 | 3ad2antl1 | |- ( ( ( ( ph /\ ps ) /\ ch /\ th ) /\ ta ) -> ph ) |