Description: Deduction introducing a disjunct. A translation of natural deduction rule \/ IR ( \/ insertion right), see natded . (Contributed by NM, 20-Sep-2007)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | orcd.1 | |- ( ph -> ps ) |
|
| Assertion | orcd | |- ( ph -> ( ps \/ ch ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | orcd.1 | |- ( ph -> ps ) |
|
| 2 | orc | |- ( ps -> ( ps \/ ch ) ) |
|
| 3 | 1 2 | syl | |- ( ph -> ( ps \/ ch ) ) |