Predicate logic in AI, also known as first-order logic (FOL), is a formal system in AI that extends propositional logic by including quantifiers and predicates. It allows more expressive representations by handling relationships between objects and their properties.

In predicate logic, statements are formed using variables, predicates (which represent properties or relations), quantifiers like ∀ (for all) and ∃ (there exists), and logical connectives. For example, "All humans are mortal" can be expressed as ∀x (Human(x) → Mortal(x)).

Predicate logic is fundamental in AI for knowledge representation, reasoning, and automated theorem proving, enabling complex inferences about the world.