Description: Introduce a left anti-conjunct to both sides of a logical equivalence. (Contributed by SF, 2-Jan-2018)
Ref | Expression | ||
---|---|---|---|
Hypothesis | nanbii.1 | |- ( ph <-> ps ) |
|
Assertion | nanbi2i | |- ( ( ch -/\ ph ) <-> ( ch -/\ ps ) ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | nanbii.1 | |- ( ph <-> ps ) |
|
2 | nanbi2 | |- ( ( ph <-> ps ) -> ( ( ch -/\ ph ) <-> ( ch -/\ ps ) ) ) |
|
3 | 1 2 | ax-mp | |- ( ( ch -/\ ph ) <-> ( ch -/\ ps ) ) |