Description: Alternate definition of the universal class (see df-v ). (Contributed by BJ, 30-Nov-2019)
Ref | Expression | ||
---|---|---|---|
Assertion | dfv2 | |- _V = { x | T. } |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-v | |- _V = { x | x = x } |
|
2 | equid | |- x = x |
|
3 | 2 | bitru | |- ( x = x <-> T. ) |
4 | 3 | abbii | |- { x | x = x } = { x | T. } |
5 | 1 4 | eqtri | |- _V = { x | T. } |