| Metamath Proof Explorer |
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Related theorems GIF version |
| Description: Extend class notation to include indexed union. |
| Ref | Expression |
|---|---|
| vx | set x |
| cA | class A |
| cB | class B |
| Ref | Expression |
|---|---|
| ciun | class ∪x ∈ A B |
| Colors of variables: wff set class |