Description: A virtual deduction elimination rule. (Contributed by Alan Sare, 24-Jun-2011) (Proof modification is discouraged.) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | e210.1 | |- (. ph ,. ps ->. ch ). | |
| e210.2 | |- (. ph ->. th ). | ||
| e210.3 | |- ta | ||
| e210.4 | |- ( ch -> ( th -> ( ta -> et ) ) ) | ||
| Assertion | e210 | |- (. ph ,. ps ->. et ). | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | e210.1 | |- (. ph ,. ps ->. ch ). | |
| 2 | e210.2 | |- (. ph ->. th ). | |
| 3 | e210.3 | |- ta | |
| 4 | e210.4 | |- ( ch -> ( th -> ( ta -> et ) ) ) | |
| 5 | 3 | vd01 | |- (. ph ->. ta ). | 
| 6 | 1 2 5 4 | e211 | |- (. ph ,. ps ->. et ). |