Description: Restricted quantifier version of one direction of 19.37 . (The other direction does not hold when A is empty.) (Contributed by FL, 13-May-2012) (Revised by Mario Carneiro, 11-Dec-2016)
Ref | Expression | ||
---|---|---|---|
Hypothesis | r19.37.1 | |- F/ x ph |
|
Assertion | r19.37 | |- ( E. x e. A ( ph -> ps ) -> ( ph -> E. x e. A ps ) ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | r19.37.1 | |- F/ x ph |
|
2 | r19.35 | |- ( E. x e. A ( ph -> ps ) <-> ( A. x e. A ph -> E. x e. A ps ) ) |
|
3 | ax-1 | |- ( ph -> ( x e. A -> ph ) ) |
|
4 | 1 3 | ralrimi | |- ( ph -> A. x e. A ph ) |
5 | 4 | imim1i | |- ( ( A. x e. A ph -> E. x e. A ps ) -> ( ph -> E. x e. A ps ) ) |
6 | 2 5 | sylbi | |- ( E. x e. A ( ph -> ps ) -> ( ph -> E. x e. A ps ) ) |