Description: Simplification of conjunction. (Contributed by NM, 9-Mar-2012) (Proof shortened by Wolf Lammen, 24-Jun-2022)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | simpl11 | |- ( ( ( ( ph /\ ps /\ ch ) /\ th /\ ta ) /\ et ) -> ph ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | simpl1 | |- ( ( ( ph /\ ps /\ ch ) /\ et ) -> ph ) | |
| 2 | 1 | 3ad2antl1 | |- ( ( ( ( ph /\ ps /\ ch ) /\ th /\ ta ) /\ et ) -> ph ) |