Description: First-order logic and set theory. (Contributed by Jonathan Ben-Naim, 3-Jun-2011) (New usage is discouraged.)
Ref | Expression | ||
---|---|---|---|
Hypotheses | bnj596.1 | |- ( ph -> A. x ph ) |
|
bnj596.2 | |- ( ph -> E. x ps ) |
||
Assertion | bnj596 | |- ( ph -> E. x ( ph /\ ps ) ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | bnj596.1 | |- ( ph -> A. x ph ) |
|
2 | bnj596.2 | |- ( ph -> E. x ps ) |
|
3 | 2 | ancli | |- ( ph -> ( ph /\ E. x ps ) ) |
4 | 1 | nf5i | |- F/ x ph |
5 | 4 | 19.42 | |- ( E. x ( ph /\ ps ) <-> ( ph /\ E. x ps ) ) |
6 | 3 5 | sylibr | |- ( ph -> E. x ( ph /\ ps ) ) |