GhostQ: System Description

Abstract

GhostQ is a DPLL-based non-CNF QBF solver. This paper describes a noteworthy feature of GhostQ that has not yet been described in the peer-reviewed literature: support for Plaisted-Greenbaum encoding. For CNF inputs, GhostQ attempts to perform reverse engineering on the CNF formula to create an equivalent circuit representation. Support for reversing the Plaisted-Greenbaum transformation was added to the existing capability for reversing the Tseitin transformation.