Description: Version of bj-isseti with a disjoint variable condition on x , V . The hypothesis uses V instead of _V for extra generality. This is indeed more general than isseti as long as elex is not available (and the non-dependence of bj-issetiv on special properties of the universal class _V is obvious). Prefer its use over bj-isseti when sufficient (in particular when V is substituted for _V ). (Contributed by BJ, 14-Sep-2019) (Proof modification is discouraged.)
Ref | Expression | ||
---|---|---|---|
Hypothesis | bj-issetiv.1 | |- A e. V |
|
Assertion | bj-issetiv | |- E. x x = A |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | bj-issetiv.1 | |- A e. V |
|
2 | elissetv | |- ( A e. V -> E. x x = A ) |
|
3 | 1 2 | ax-mp | |- E. x x = A |