Description: Theorem 19.29 of Margaris p. 90. See also 19.29r . (Contributed by NM, 21-Jun-1993) (Proof shortened by Andrew Salmon, 13-May-2011)
Ref | Expression | ||
---|---|---|---|
Assertion | 19.29 | |- ( ( A. x ph /\ E. x ps ) -> E. x ( ph /\ ps ) ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | pm3.2 | |- ( ph -> ( ps -> ( ph /\ ps ) ) ) |
|
2 | 1 | aleximi | |- ( A. x ph -> ( E. x ps -> E. x ( ph /\ ps ) ) ) |
3 | 2 | imp | |- ( ( A. x ph /\ E. x ps ) -> E. x ( ph /\ ps ) ) |