Description: Inference from Theorem 19.21 of Margaris p. 90. (Restricted quantifier version with double quantification.) (Contributed by NM, 2-Feb-2008)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | ralrimdvva.1 | |- ( ( ph /\ ( x e. A /\ y e. B ) ) -> ( ps -> ch ) ) | |
| Assertion | ralrimdvva | |- ( ph -> ( ps -> A. x e. A A. y e. B ch ) ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | ralrimdvva.1 | |- ( ( ph /\ ( x e. A /\ y e. B ) ) -> ( ps -> ch ) ) | |
| 2 | 1 | ex | |- ( ph -> ( ( x e. A /\ y e. B ) -> ( ps -> ch ) ) ) | 
| 3 | 2 | com23 | |- ( ph -> ( ps -> ( ( x e. A /\ y e. B ) -> ch ) ) ) | 
| 4 | 3 | ralrimdvv | |- ( ph -> ( ps -> A. x e. A A. y e. B ch ) ) |