In mathematical logic, a literal is an atomic formula without 0 and 1, or its logical negation . Accordingly, two types of literals are shared:
- A positive literal is directly an atomic formula .
- A negative literal is the logical negation of an atomic formula .
A literal in propositional logic
In the logic of utterances, a literal is a logical variable or its logical negation . Accordingly, a positive literal is called the variable itself, and a negative literal is the logical negation of the variable .