Description: An inference based on modus ponens. (Contributed by NM, 23-May-1999) (Proof shortened by Wolf Lammen, 22-Nov-2012)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | mpdan.1 | |- ( ph -> ps ) |
|
| mpdan.2 | |- ( ( ph /\ ps ) -> ch ) |
||
| Assertion | mpdan | |- ( ph -> ch ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | mpdan.1 | |- ( ph -> ps ) |
|
| 2 | mpdan.2 | |- ( ( ph /\ ps ) -> ch ) |
|
| 3 | id | |- ( ph -> ph ) |
|
| 4 | 3 1 2 | syl2anc | |- ( ph -> ch ) |