Description: Simplification of conjunction. (Contributed by Jeff Hankins, 17-Nov-2009) (Proof shortened by Wolf Lammen, 23-Jun-2022)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | simpl1 | |- ( ( ( ph /\ ps /\ ch ) /\ th ) -> ph ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | simpl | |- ( ( ph /\ th ) -> ph ) |
|
| 2 | 1 | 3ad2antl1 | |- ( ( ( ph /\ ps /\ ch ) /\ th ) -> ph ) |