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 .)