Description: Simplification of conjunction. (Contributed by NM, 9-Mar-2012) (Proof shortened by Wolf Lammen, 24-Jun-2022)
Ref | Expression | ||
---|---|---|---|
Assertion | simpr21 | |- ( ( et /\ ( th /\ ( ph /\ ps /\ ch ) /\ ta ) ) -> ph ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | simpr1 | |- ( ( et /\ ( ph /\ ps /\ ch ) ) -> ph ) |
|
2 | 1 | 3ad2antr2 | |- ( ( et /\ ( th /\ ( ph /\ ps /\ ch ) /\ ta ) ) -> ph ) |