Description: Deduction introducing an embedded antecedent. Deduction form of ax-1 and a1i . (Contributed by NM, 5-Jan-1993) (Proof shortened by Stefan Allan, 20-Mar-2006)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | a1d.1 | |- ( ph -> ps ) |
|
| Assertion | a1d | |- ( ph -> ( ch -> ps ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | a1d.1 | |- ( ph -> ps ) |
|
| 2 | ax-1 | |- ( ps -> ( ch -> ps ) ) |
|
| 3 | 1 2 | syl | |- ( ph -> ( ch -> ps ) ) |