Description: The intersection of a nonempty class abstraction exists. (Contributed by NM, 21-Oct-2003)
Ref | Expression | ||
---|---|---|---|
Assertion | intexab | |- ( E. x ph <-> |^| { x | ph } e. _V ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | abn0 | |- ( { x | ph } =/= (/) <-> E. x ph ) |
|
2 | intex | |- ( { x | ph } =/= (/) <-> |^| { x | ph } e. _V ) |
|
3 | 1 2 | bitr3i | |- ( E. x ph <-> |^| { x | ph } e. _V ) |