Lambda Calculus and Functional Programming

Prolog uses the prefix operator "\+" to represent a negated predicate. Why is this: The semantics of Prolog's implementation is poorly understood and so it is given a random ascii code The original authors of Prolog were hoping to introduce "not" as a form of negation with a full logical semantics The characters "\+" provided an ascii representation that was similar to the logical symbol for "it is not provable that" No one is quite sure, but it is used now as a convention