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Description: Restricted quantifier version of one direction of 19.36 . (The other direction holds iff A is nonempty, see r19.36zv .) (Contributed by NM, 22-Oct-2003)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | r19.36v | |- ( E. x e. A ( ph -> ps ) -> ( A. x e. A ph -> ps ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | r19.35 | |- ( E. x e. A ( ph -> ps ) <-> ( A. x e. A ph -> E. x e. A ps ) ) |
|
| 2 | id | |- ( ps -> ps ) |
|
| 3 | 2 | rexlimivw | |- ( E. x e. A ps -> ps ) |
| 4 | 3 | imim2i | |- ( ( A. x e. A ph -> E. x e. A ps ) -> ( A. x e. A ph -> ps ) ) |
| 5 | 1 4 | sylbi | |- ( E. x e. A ( ph -> ps ) -> ( A. x e. A ph -> ps ) ) |