Description: Prove an existential. (Contributed by Rohan Ridenour, 12-Aug-2023)
Ref | Expression | ||
---|---|---|---|
Hypotheses | rr-spce.1 | |- ( ( ph /\ x = A ) -> ps ) |
|
rr-spce.2 | |- ( ph -> A e. V ) |
||
Assertion | rr-spce | |- ( ph -> E. x ps ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | rr-spce.1 | |- ( ( ph /\ x = A ) -> ps ) |
|
2 | rr-spce.2 | |- ( ph -> A e. V ) |
|
3 | 2 | elexd | |- ( ph -> A e. _V ) |
4 | isset | |- ( A e. _V <-> E. x x = A ) |
|
5 | 3 4 | sylib | |- ( ph -> E. x x = A ) |
6 | 1 | ex | |- ( ph -> ( x = A -> ps ) ) |
7 | 6 | eximdv | |- ( ph -> ( E. x x = A -> E. x ps ) ) |
8 | 5 7 | mpd | |- ( ph -> E. x ps ) |