Description: Deduction eliminating a conjunct. (Contributed by NM, 27-May-1998)
Ref | Expression | ||
---|---|---|---|
Hypothesis | simplbi.1 | |- ( ph <-> ( ps /\ ch ) ) |
|
Assertion | simplbi | |- ( ph -> ps ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | simplbi.1 | |- ( ph <-> ( ps /\ ch ) ) |
|
2 | 1 | biimpi | |- ( ph -> ( ps /\ ch ) ) |
3 | 2 | simpld | |- ( ph -> ps ) |