Description: Version of 19.32 with a disjoint variable condition, requiring fewer axioms. (Contributed by BJ, 7-Mar-2020)
Ref | Expression | ||
---|---|---|---|
Assertion | 19.32v | |- ( A. x ( ph \/ ps ) <-> ( ph \/ A. x ps ) ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 19.21v | |- ( A. x ( -. ph -> ps ) <-> ( -. ph -> A. x ps ) ) |
|
2 | df-or | |- ( ( ph \/ ps ) <-> ( -. ph -> ps ) ) |
|
3 | 2 | albii | |- ( A. x ( ph \/ ps ) <-> A. x ( -. ph -> ps ) ) |
4 | df-or | |- ( ( ph \/ A. x ps ) <-> ( -. ph -> A. x ps ) ) |
|
5 | 1 3 4 | 3bitr4i | |- ( A. x ( ph \/ ps ) <-> ( ph \/ A. x ps ) ) |