Skolem normal form
A
formula of
first-order logic is in
Skolem normal form if its
prenex normal form has only universal quantifiers. A formula can be
Skolemized, that is have its existential quantifiers eliminated to produce an equisatisfiable formula to the original. The essence of skolemization is the observation that if a formula in the form is satisfiable in some
model, then there must be some point in the model for every which makes true, and there will be some function which makes the formula hold in this model. The function f is called a skolem function.