Hintikka set
In mathematical logic, a Hintikka set is a set of
logical formulas
whose elements satisfy the following properties:
- An atom or its conjugate can appear in the set but not both,
- If a formula in the set has a main operator that is of "conjuctive-type", then its two operands appear in the set,
- If a formula in the set has a main operator that is of "disjuntive-type", then at least one of its two operands appears in the set.
The exact meaning of "conjuctive-type" and "disjunctive-type" is defined by the method of
semantic tableaux
.
Hintikka sets arise when attempting to prove completeness of propositional logic using
semantic tableaux. They are named after Jaakko Hintikka
.
Propositional Hintikka sets
In a semantic tableau for propositional logic, Hintikka sets can be defined using uniform notation for propositional tableaux. The elements of a propositional Hintikka set S satisfy the following conditions:[1]
- No variable and its conjugate are both in S,
- For any in S, its components are both in S,
- For any in S, at least one of its components are in S.
If a set S is a Hintikka set, then S is
satisfiable
.
References
- ISBN 0486492370.
Sources
- LCCN 68-13495.