3 papers
math.LO2026
Uncountably many maximally consistent neighborhood complete congruential modal logics
Zalán Gyenis, Krzysztof Krawczyk
We solve an open problem posed by Peter Fritz in \cite{Fritz} by proving that there are uncountably many C-Post complete congruential modal logics which are neighborhood complete.…
math.LO2025
Maehara Interpolation in Extensions of R-mingle
Wesley Fussner, Krzysztof Krawczyk
We show that there are exactly five quasivarieties of Sugihara algebras with the amalgamation property, and that all of these have the relative congruence extension property. As a…
math.LO2024
Epstein Semantics: Characterization, Interpolation, Undefinability, and (In)Completeness
Krzysztof A. Krawczyk
This paper is a mathematical investigation on Epstein semantics. One of the main tools of the present paper is the model-theoretic S-set construction introduced in (Krawczyk 2022).…