Description: Simplification of conjunction. (Contributed by NM, 9-Mar-2012) (Proof shortened by Wolf Lammen, 24-Jun-2022)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | simpl23 | |- ( ( ( th /\ ( ph /\ ps /\ ch ) /\ ta ) /\ et ) -> ch ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | simpl3 | |- ( ( ( ph /\ ps /\ ch ) /\ et ) -> ch ) |
|
| 2 | 1 | 3ad2antl2 | |- ( ( ( th /\ ( ph /\ ps /\ ch ) /\ ta ) /\ et ) -> ch ) |