
11Logics of Space with Connectedness Predicates: Complete AxiomatizationsIn Marcus Kracht, Maarten de Rijke, Heinrich Wansing & Michael Zakharyaschev (eds.), Advances in Modal Logic, Csli Publications. pp. 434453. 1998.

34Secondorder logic on equivalence relationsJournal of Applied NonClassical Logics 18 (23): 229246. 2008.In this paper we investigate several extensions of the first orderlanguage with finitely many binary relations. The most interesting of the studied extensions appears to be the monadic secondorder one. We show that the extended languages have the same expressive power as the firstorder language over the class of all relational structures of equivalence relations in local agreement by providing appropriate translation of formulae. The decidability of the considered extensions over the above me…Read more

33Dynamic logics of the regionbased theory of discrete spacesJournal of Applied NonClassical Logics 17 (1): 3961. 2007.The aim of this paper is to give new kinds of modal logics suitable for reasoning about regions in discrete spaces. We call them dynamic logics of the regionbased theory of discrete spaces. These modal logics are linguistic restrictions of propositional dynamic logic with the global diamond E. Their formulas are equivalent to Boolean combinations of modal formulas like E(A ∧ ⟨α⟩ B) where A and B are Boolean terms and α is a relational term. Examining what we can say about dynamic models when we…Read more

32Remarks about the unification types of some locally tabular normal modal logicsLogic Journal of the IGPL 31 (1): 115139. 2023.It is already known that unifiable formulas in normal modal logic $\textbf {K}+\square ^{2}\bot $ are either finitary or unitary and unifiable formulas in normal modal logic $\textbf {Alt}_{1}+\square ^{2}\bot $ are unitary. In this paper, we prove that for all $d{\geq }3$, unifiable formulas in normal modal logic $\textbf {K}+\square ^{d}\bot $ are either finitary or unitary and unifiable formulas in normal modal logic $\textbf {Alt}_{1}+\square ^{d}\bot $ are unitary.

51Modal Definability: Two Commuting Equivalence RelationsLogica Universalis 16 (1): 177194. 2022.We prove that modal definability with respect to the class of all structures with two commuting equivalence relations is an undecidable problem. The construction used in the proof shows that the same is true for the subclass of all finite structures. For that reason we prove that the firstorder theories of these classes are undecidable and reduce the latter problem to the former.

5Logics of Space with Connectedness Predicates: Complete AxiomatizationsIn Marcus Kracht, Maarten de Rijke, Heinrich Wansing & Michael Zakharyaschev (eds.), Advances in Modal Logic, Csli Publications. pp. 434453. 1998.

39Mixed algebras and their logicsJournal of Applied NonClassical Logics 27 (34): 304320. 2017.We investigate complex algebras of the form arising from a frame where, and exhibit their abstract algebraic and logical counterparts.

12Unification in modal logic Alt1In Lev Beklemishev, Stéphane Demri & András Máté (eds.), Advances in Modal Logic, Volume 11, Csli Publications. pp. 117134. 2016.

7Definability and Computability for PRSPDLIn Rajeev Goré, Barteld Kooi & Agi Kurucz (eds.), Advances in Modal Logic, Volume 10: Papers From the Tenth Aiml Conference, Held in Groningen, the Netherlands, August 2014, Csli Publications. pp. 1633. 2014.