Skolemization
E822885
Skolemization is a logical transformation technique that eliminates existential quantifiers by introducing Skolem functions or constants, commonly used in automated theorem proving and first-order logic.
Observed surface forms (2)
| Surface form | Occurrences |
|---|---|
| Skolem normal form | 2 |
| Skolem function | 1 |
Statements (47)
| Predicate | Object |
|---|---|
| instanceOf |
logical transformation technique
ⓘ
method in first-order logic ⓘ technique in automated theorem proving ⓘ |
| appliedAfter | prenex normal form transformation ⓘ |
| appliedBefore |
Herbrand expansion
NERFINISHED
ⓘ
clausal form conversion ⓘ |
| assumes | non-empty domain of discourse ⓘ |
| assumption | classical first-order logic semantics ⓘ |
| commonUsage |
standard preprocessing step in automated theorem provers
ⓘ
standard step in converting formulas to CNF ⓘ |
| conditionForSkolemConstant | existential quantifier not within scope of universal quantifiers ⓘ |
| conditionForSkolemFunction | existential quantifier within scope of universal quantifiers ⓘ |
| doesNotPreserve | logical equivalence in general ⓘ |
| effectOnQuantifiers |
removes existential quantifiers
ⓘ
retains universal quantifiers or moves them outward ⓘ |
| field |
automated reasoning
ⓘ
first-order logic ⓘ mathematical logic ⓘ |
| historicalOrigin | work of Thoralf Skolem in early 20th century ⓘ |
| input | first-order logic formula in prenex form ⓘ |
| introduces |
new constant symbols
ⓘ
new function symbols ⓘ |
| limitation | not directly applicable to second-order quantifiers ⓘ |
| namedAfter | Thoralf Skolem NERFINISHED ⓘ |
| output | first-order logic formula without existential quantifiers ⓘ |
| preserves | satisfiability ⓘ |
| property |
can increase signature of the language
ⓘ
produces equisatisfiable formula ⓘ |
| purpose |
eliminate existential quantifiers
ⓘ
prepare formulas for resolution-based theorem proving ⓘ transform formulas into equisatisfiable form ⓘ |
| relatedConcept |
Herbrand’s theorem
NERFINISHED
ⓘ
Skolem constant NERFINISHED ⓘ Skolem function NERFINISHED ⓘ Skolem normal form NERFINISHED ⓘ clausal normal form ⓘ prenex normal form ⓘ |
| replaces | existentially quantified variables ⓘ |
| typicalStepIn |
conversion to clausal normal form
GENERATED
ⓘ
preprocessing for resolution calculus GENERATED ⓘ |
| usedIn |
Prolog implementation
ⓘ
logic programming ⓘ model checking preprocessors ⓘ resolution theorem proving ⓘ tableaux methods ⓘ |
| uses |
Skolem constants
NERFINISHED
ⓘ
Skolem functions NERFINISHED ⓘ |
Referenced by (6)
Full triples — surface form annotated when it differs from this entity's canonical label.
this entity surface form:
Skolem normal form
this entity surface form:
Skolem normal form
this entity surface form:
Skolem function