Metamath Proof Explorer

Syntax definition co

Description: Extend class notation to include the value of an operation F (such as + ) for two arguments A and B . Note that the syntax is simply three class symbols in a row surrounded by parentheses. Since operation values are the only possible class expressions consisting of three class expressions in a row surrounded by parentheses, the syntax is unambiguous. (For an example of how syntax could become ambiguous if we are not careful, see the comment in cneg .)

Ref Expression
Assertion co
class ( A F B )