Description: The Axiom of Union in class notation. This says that if A is a set i.e. A e. _V (see isset ), then the union of A is also a set. Same as Axiom 3 of TakeutiZaring p. 16. (Contributed by NM, 11-Aug-1993)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | uniex.1 | |- A e. _V |
|
| Assertion | uniex | |- U. A e. _V |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | uniex.1 | |- A e. _V |
|
| 2 | uniexg | |- ( A e. _V -> U. A e. _V ) |
|
| 3 | 1 2 | ax-mp | |- U. A e. _V |