Description: Extend class notation to include indexed union. Note: Historically (prior to 21-Oct-2005), set.mm used the notation U. x e. A B , with the same union symbol as cuni . While that syntax was unambiguous, it did not allow for LALR parsing of the syntax constructions in set.mm. The new syntax uses a distinguished symbol U_ instead of U. and does allow LALR parsing. Thanks to Peter Backes for suggesting this change.
| Ref | Expression | ||
|---|---|---|---|
| Assertion | ciun | class ∪ 𝑥 ∈ 𝐴 𝐵 |