Description: Equivalence with a conjunction one of whose conjuncts is a consequence of the other. Deduction form. (Contributed by Zhi Wang, 27-Sep-2024)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | mpbiran3d.1 | |- ( ph -> ( ps <-> ( ch /\ th ) ) ) | |
| mpbiran4d.2 | |- ( ( ph /\ th ) -> ch ) | ||
| Assertion | mpbiran4d | |- ( ph -> ( ps <-> th ) ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | mpbiran3d.1 | |- ( ph -> ( ps <-> ( ch /\ th ) ) ) | |
| 2 | mpbiran4d.2 | |- ( ( ph /\ th ) -> ch ) | |
| 3 | 1 | biancomd | |- ( ph -> ( ps <-> ( th /\ ch ) ) ) | 
| 4 | 3 2 | mpbiran3d | |- ( ph -> ( ps <-> th ) ) |