Simplifying query-answering problems by unfolding

To convert a first-order formula containing an existential quantification into an equivalent clausal normal form, it is necessary to introduce function variables and accordingly extend the space of first-order formulas. This paper proposes unfolding transformation in such an extended formula space and demonstrates how it is employed to simplify queryanswering problems. The presented work provides a foundation for constructing a correct method for solving queryanswering problems that include unrestricted use of universal and existential quantifications.

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