Implementing analytic tableaux for justification logic

Abstract

This Master's thesis presents new decidable tableau systems for the justification logics J and LP, and proves their soundness and completeness by providing a proof of cut-elimination. The accompanying Haskell software, "judge", is able to automatically construct tableau proofs for any tableau system defined by the user, including the proposed systems. The crux lies in its ability to deal with systems in which the expansion rules may introduce formulas that are not subterms of formulas that previously occurred on the branch.