Abstract
This is an Isabelle/HOL formalisation of the semantics of the
multi-valued planning tasks language that is used by the planning
system Fast-Downward, the STRIPS fragment of the Planning Domain
Definition Language (PDDL), and the STRIPS soundness meta-theory
developed by Vladimir Lifschitz. It also contains formally verified
checkers for checking the well-formedness of problems specified in
either language as well the correctness of potential solutions. The
formalisation in this entry was described in an earlier publication.