Description: A simplification of class abstraction. Commuted form of abid1 . See comments there. (Contributed by NM, 26-Dec-1993)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | abid2 | |- { x | x e. A } = A | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | abid1 |  |-  A = { x | x e. A } | |
| 2 | 1 | eqcomi |  |-  { x | x e. A } = A |