gienah@gentoo.org sci-mathematics@gentoo.org Gentoo Mathematics Project Kodkod is an efficient SAT-based constraint solver for first order logic with relations, transitive closure, bit-vector arithmetic, and partial models. It provides analyses for both satisfiable and unsatisfiable problems: a finite model finder for the former and a minimal unsatisfiable core extractor for the latter. Kodkod is used in a wide range of applications, including code checking, test-case generation, declarative execution, declarative configuration, and lightweight analysis of Alloy, UML, and Isabelle/HOL.