Abstract
The simplest combination of unimodal logics \({\mathrm{L}_1 \rm and \mathrm{L}_2}\) into a bimodal logic is their fusion, \({\mathrm{L}_1 \otimes \mathrm{L}_2}\), axiomatized by the theorems of \({\mathrm{L}_1 \rm for \square_1 \rm and of \mathrm{L}_2 \rm for \square_{2}}\). Shehtman introduced combinations that are not only bimodal, but two-dimensional: he defined 2-d Cartesian products of 1-d Kripke frames, using these Cartesian products to define the frame product \({\mathrm{L}_1 \times \mathrm{L}_2 \rm of \mathrm{L}_1 \rm and \mathrm{L}_2}\). Van Benthem, Bezhanishvili, ten Cate and Sarenac generalized Shehtman’s idea and introduced the topological product \({\mathrm{L}_1 \times_{t}\mathrm{L}_2}\), using Cartesian products of topological spaces rather than of Kripke frames. Frame products have been extensively studied, but much less is known about topological products. The goal of the current paper is to give necessary and sufficient conditions for the topological product to match the frame product, for Kripke complete extensions of \({\mathrm{S}4: \mathrm{L}_1 \times_t \mathrm{L}_2 = \mathrm{L}_1 \times \mathrm{L}_2 \rm iff \mathrm{L}_1 \supsetneq \mathrm{S}5 \rm or \mathrm{L}_2 \supsetneq \mathrm{S}5 \rm or \mathrm{L}_1, \mathrm{L}_2 = \mathrm{S}5}\).
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References
Bezhanishvili G., Esakia L., Gabelaia D.: Some results on modal axiomatization and definability for topological spaces. Studia Logica 81, 325–355 (2005)
Blok W.J.: The lattice of modal logics: an algebraic investigation. Journal of Symbolic Logic 45, 221–236 (1980)
Chagrov, A., and M. Zakharyaschev, Modal Logic, Oxford Logic Guides, Vol. 35, Clarendon Press, Oxford, 1997.
Gabbay, D. M., and V. B. Shehtman, Products of modal logics, part 1, Logic Journal of the IGPL 1:73–146, 1998. http://jigpal.oxfordjournals.org/cgi/reprint/6/1/73.
Gabbay, D. M., A. Kurucz, F. Wolter, and M. Zakharyaschev, Many-Dimensional Modal Logics: Theory and Applications, Studies in Logic and the Foundations of Mathematics, Vol. 148, Elsevier, Amsterdam, 2003.
Kremer, P., The topological product of S4 and S5, ms., http://www.individual.utoronto.ca/philipkremer/onlinepapers/TopS4xS5.
Kurucz, A., Combining modal logics, in J. van Benthem, P. Blackburn, and F. Wolter (eds.), Handbook of Modal Logic, Studies in Logic and Practical Reasoning 3, Elsevier, Amsterdam, 2007, pp. 869–926, http://www.dcs.kcl.ac.uk/staff/kuag/publi/combi.ps.
Kurucz, A., and M. Zakharyaschev, A note on relativised products of modal logics, in P. Balbiani, N.-Y. Suzuki, F. Wolter, and M. Zakharyaschev (eds.), Advances in Modal Logic, Vol. 4, King’s College Publications, 2003, pp. 221–242, http://www.aiml.net/volumes/volume4/Kurucz-Zakharyaschev.ps.
McKinsey J.C.C., McKinsey J.C.C.: solution of the decision problem for the Lewis systems S2 and S4, with an application to topology. The Journal of Symbolic Logic 6, 117–134 (1941)
McKinsey J.C.C., Tarski A.: The algebra of topology. Annals of Mathematics 45, 141–191 (1944)
Rasiowa H., Sikorski R.: The Mathematics of Metamathematics. Państowowe Wydawnictwo Naukowe, Warsaw (1963)
Scroggs S.J.: Extensions of the Lewis system S5. The Journal of Symbolic Logic 16, 112–120 (1951)
Shehtman, V. B., Two-dimensional modal logics (in Russian), Matematicheskie Zametki 23:773–781, 1978. English translation, Mathematical Notes 23:417–424, 1978.
Shehtman, V. B., Two-dimensional modal logics and relativized quantifiers, Advances in Modal Logic ’98, Extended Abstracts, Uppsala, 1998, pp. 226–373.
van Benthem J., Bezhanishvili G., ten Cate B., Sarenac D.: Multimodal logics of products of topologies. Studia Logica 84, 369–392 (2006)
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Kremer, P. Matching Topological and Frame Products of Modal Logics. Stud Logica 104, 487–502 (2016). https://doi.org/10.1007/s11225-015-9648-6
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DOI: https://doi.org/10.1007/s11225-015-9648-6