论文信息 - On Skolemization and Proof Complexity

On Skolemization and Proof Complexity

The impact of Skolemization on the complexity of proofs in the sequent calculus is investigated. It is shown that prefix Skolemization may result in a nonelementary increase of Herbrand complexity (i. e. the minimal number of constituents in a Herbrand disjunction) versus structural Skolemization. Moreover it is shown that restricting the range of quantifiers never increases Herbrand complexity. The results provide a general mathematical justification for minimizing the range of quantifiers (by means of shifting) before Skolemization of formulas.

Alexander Leitsch | Matthias Baaz | M. Baaz | A. Leitsch

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