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Skolem normal form
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<p>In <a href="/facts/Mathematical_logic/SaI7Y3wN">mathematical logic</a>, a <a href="/facts/Well-formed_formula/YpTVlzuj">formula</a> of <a href="/facts/First-order_logic/lcISqWIg">first-order logic</a> is in Skolem normal form if it is in <a href="/facts/Prenex_normal_form/D0UCl45n">prenex normal form</a> with only <a href="/facts/Universal_quantification/agNmvJKN">universal first-order quantifiers</a>. </p><p>Every first-order <a href="/facts/Well-formed_formula/YpTVlzuj">formula</a> may be converted into Skolem normal form while not changing its <a href="/facts/Satisfiability/NkmQFgHB">satisfiability</a> via a process called Skolemization (sometimes spelled Skolemnization). The resulting formula is not necessarily <a href="/facts/Logical_equivalence/ysCWmsxA">equivalent</a> to the original one, but is <a href="/facts/Equisatisfiable/p43Q7zMt">equisatisfiable</a> with it: it is satisfiable if and only if the original one is satisfiable. </p><p>Reduction to Skolem normal form is a method for removing <a href="/facts/Existential_quantification/hHveaBYo">existential quantifiers</a> from <a href="/facts/Formal_logic/SaI7Y3wN">formal logic</a> statements, often performed as the first step in an <a href="/facts/Automated_theorem_prover/vKGvuKFI">automated theorem prover</a>. </p>