Description: el021old without virtual deductions. (Contributed by Alan Sare, 13-Jun-2015) (Proof modification is discouraged.) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | eel021.1 | |- ph | |
| eel021.2 | |- ( ( ps /\ ch ) -> th ) | ||
| eel021.3 | |- ( ( ph /\ th ) -> ta ) | ||
| Assertion | eel021old | |- ( ( ps /\ ch ) -> ta ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | eel021.1 | |- ph | |
| 2 | eel021.2 | |- ( ( ps /\ ch ) -> th ) | |
| 3 | eel021.3 | |- ( ( ph /\ th ) -> ta ) | |
| 4 | 1 2 3 | sylancr | |- ( ( ps /\ ch ) -> ta ) |