PP201703: Bezhanishvili, Nick and Marra, Vincenzo and McNeill, Daniel and Pedrini, Andrea (2017) Tarski's theorem on intuitionistic logic, for polyhedra. [Preprint]

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Abstract
In 1938, Tarski proved that a formula is not intuitionistically valid if, and only if, it has a countermodel in the Heyting algebra of open sets of some topological space. In fact, Tarski showed that any Euclidean space R^n with n > 1 suffices, as does e.g. the Cantor space. In particular, intuitionistic logic cannot detect topological dimension in the frame of all open sets of a Euclidean space. By contrast, we consider the lattice of open subpolyhedra of a given compact polyhedron P of R^n, prove that it is a locally finite Heyting subalgebra of the (nonlocallyfinite) algebra of all open sets of R^n, and show that intuitionistic logic is able to capture the topological dimension of P through the boundeddepth axiom schemata. Further, we show that intuitionistic logic is precisely the logic of formulas valid in all Heyting algebras arising from polyhedra in this manner. Thus, our main theorem reconciles through polyhedral geometry two classical results: topological completeness in the style of Tarski, and Jaskowski's theorem that intuitionistic logic enjoys the finite model property. Several questions of interest remain open. E.g., what is the intermediate logic of all closed triangulable manifolds?
Item Type:  Preprint 

Report Nr:  PP201703 
Series Name:  Prepublication (PP) Series 
Year:  2017 
Subjects:  Logic 
Depositing User:  Nick Bezhanishvili 
Date Deposited:  18 Jan 2017 21:28 
Last Modified:  18 Jan 2017 21:31 
URI:  https://eprints.illc.uva.nl/id/eprint/1520 
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