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. } |