Negation as failure

Negation as failure is a concept primarily used in logic programming and non-monotonic reasoning, notably in the field of artificial intelligence and computational logic. It is a way of handling negation in a way that is consistent with the principle of closed world assumption (CWA). In classical logic, a statement can either be true or false, and the truth of a statement can be proven with evidence. However, in many practical applications, we often deal with incomplete knowledge about a system or domain.