Description: Two virtual hypotheses virtually infer a theorem. (Contributed by Alan Sare, 14-Jun-2011) (Proof modification is discouraged.) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | vd02.1 | |- ph |
|
| Assertion | vd02 | |- (. ps ,. ch ->. ph ). |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | vd02.1 | |- ph |
|
| 2 | 1 | a1i | |- ( ch -> ph ) |
| 3 | 2 | a1i | |- ( ps -> ( ch -> ph ) ) |
| 4 | 3 | dfvd2ir | |- (. ps ,. ch ->. ph ). |