Description: Restricted quantifier version of 19.29r ; variation of r19.29 . (Contributed by NM, 31-Aug-1999) (Proof shortened by Wolf Lammen, 29-Jun-2023)
Ref | Expression | ||
---|---|---|---|
Assertion | r19.29r | |- ( ( E. x e. A ph /\ A. x e. A ps ) -> E. x e. A ( ph /\ ps ) ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | iba | |- ( ps -> ( ph <-> ( ph /\ ps ) ) ) |
|
2 | 1 | ralrexbid | |- ( A. x e. A ps -> ( E. x e. A ph <-> E. x e. A ( ph /\ ps ) ) ) |
3 | 2 | biimpac | |- ( ( E. x e. A ph /\ A. x e. A ps ) -> E. x e. A ( ph /\ ps ) ) |