Description: Definition of a 2-hypothesis virtual deduction. (Contributed by Alan Sare, 14-Nov-2011) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | df-vd2 | |- ( (. ph ,. ps ->. ch ). <-> ( ( ph /\ ps ) -> ch ) ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 0 | wph | |- ph | |
| 1 | wps | |- ps | |
| 2 | wch | |- ch | |
| 3 | 0 1 2 | wvd2 | |- (. ph ,. ps ->. ch ). | 
| 4 | 0 1 | wa | |- ( ph /\ ps ) | 
| 5 | 4 2 | wi | |- ( ( ph /\ ps ) -> ch ) | 
| 6 | 3 5 | wb | |- ( (. ph ,. ps ->. ch ). <-> ( ( ph /\ ps ) -> ch ) ) |