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| Description: Extend wff notation to include the general binary relation predicate. Note that the syntax is simply three class symbols in a row. Since binary relations are the only possible wff expressions consisting of three class expressions in a row, the syntax is unambiguous. (For an example of how syntax could become ambiguous if we are not careful, see the comment in cneg 5273.) |
| Ref | Expression |
|---|---|
| cA | class A |
| cB | class B |
| cR | class R |
| Ref | Expression |
|---|---|
| wbr | wff ARB |
| Colors of variables: wff set class |