Description: Add top ad a conjunct. (Contributed by Giovanni Mascellani, 24-May-2019)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | tradd.1 | |- ( ph <-> ps ) | |
| Assertion | tradd | |- ( ph <-> ( T. /\ ps ) ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | tradd.1 | |- ( ph <-> ps ) | |
| 2 | truan | |- ( ( T. /\ ps ) <-> ps ) | |
| 3 | 1 2 | bitr4i | |- ( ph <-> ( T. /\ ps ) ) |