arXiv subjects

Niels C. Vooijs

Publications and source records attributed to Niels C. Vooijs.

2 recordsLinked to original sources

arXiv2026

Logics Containing wK4: Selection à la Fine

We generalize Fine's Iterative Selection Method to the weakly transitive setting. In particular, this provides a transparent frame-theoretic proof of the finite model property for (strongly) cofinal subframe logics extending wK4, which was previously established using algebraic methods. Using the same construction, we generalize Fine's Finite Width Theorem to the weakly transitive setting, connecting these two celebrated theorems of Fine.

cs.LO↗

arXiv2026

Interpolation above S4

We complete Maksimova's classification of the normal extensions of S4 with interpolation. In particular, we prove Craig interpolation for the six extensions of S4 for which Craig interpolation was still open. The proof strategy builds upon the ideas of Smoryński, but employs a novel approach using Fine's frame formulas for splitting clusters.

math.LO↗