Description: Simplification of conjunction. (Contributed by NM, 9-Mar-2012) (Proof shortened by Wolf Lammen, 24-Jun-2022)
Ref | Expression | ||
---|---|---|---|
Assertion | simpl21 | |- ( ( ( th /\ ( ph /\ ps /\ ch ) /\ ta ) /\ et ) -> ph ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | simpl1 | |- ( ( ( ph /\ ps /\ ch ) /\ et ) -> ph ) |
|
2 | 1 | 3ad2antl2 | |- ( ( ( th /\ ( ph /\ ps /\ ch ) /\ ta ) /\ et ) -> ph ) |