Metamath Proof Explorer

Syntax definition ciin

Description: Extend class notation to include indexed intersection. Note: Historically (prior to 21-Oct-2005), used the notation |^| x e. A B , with the same intersection symbol as cint . Although that syntax was unambiguous, it did not allow for LALR parsing of the syntax constructions in The new syntax uses a distinguished symbol |^|_ instead of |^| and does allow LALR parsing. Thanks to Peter Backes for suggesting this change.

Ref Expression
Assertion ciin class x A B