Description: Simplification of conjunction. (Contributed by NM, 9-Mar-2012) (Proof shortened by Wolf Lammen, 24-Jun-2022)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | simpr31 | |- ( ( et /\ ( th /\ ta /\ ( ph /\ ps /\ ch ) ) ) -> ph ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | simpr1 | |- ( ( et /\ ( ph /\ ps /\ ch ) ) -> ph ) | |
| 2 | 1 | 3ad2antr3 | |- ( ( et /\ ( th /\ ta /\ ( ph /\ ps /\ ch ) ) ) -> ph ) |