Description: The Russell class is equal to the universe _V . Exercise 5 of TakeutiZaring p. 22. (Contributed by Alan Sare, 4-Oct-2008)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | ruv | |- { x | x e/ x } = _V |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | vex | |- x e. _V |
|
| 2 | elirr | |- -. x e. x |
|
| 3 | 2 | nelir | |- x e/ x |
| 4 | 1 3 | 2th | |- ( x e. _V <-> x e/ x ) |
| 5 | 4 | eqabi | |- _V = { x | x e/ x } |
| 6 | 5 | eqcomi | |- { x | x e/ x } = _V |