On Local Finiteness of Modal K4 Algebras
Abstract
We study local finiteness for modal K4 algebras via the tunability of their dual general frames. In particular, we provide a sufficient condition for modal K4 algebras to be locally finite by identifying a structure which must be present in non-locally finite modal K4 algebras. We then show that this condition becomes both necessary and sufficient for σ-complete modal K4 algebras. Next, we translate this condition into a pair of order-theoretic conditions on transitive Kripke frames, providing a classification of local finiteness on their dual modal algebras. We further show that the logic of any class of well-founded transitive relations with no infinite antichains has the finite model property, and conclude that the logic of the class of well-quasi orderings has the finite model property.
Related
- Representation Type and Schurian Finiteness of Tits Algebras
- Failure of direct finiteness for group algebras in every odd characteristic
- Modular Functors with Singularities from Vertex Operator Algebras Beyond Rigidity and Finiteness
- Geometric Detection and Finiteness of Crystalline Local Systems
- Diameter Bounds and Finiteness of Graphs from Local Intersection Data
BibTeX
@misc{agnew2026local,
title = {{On Local Finiteness of Modal K4 Algebras}},
author = {Gabriel Agnew},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2606.02941},
eprint = {2606.02941},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2606.02941},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - On Local Finiteness of Modal K4 Algebras
AU - Gabriel Agnew
PY - 2026
DA - 2026/10/30
PB - arXiv
DO - 10.48550/arxiv.2606.02941
UR - https://arxiv.org/abs/2606.02941
AB - We study local finiteness for modal K4 algebras via the tunability of their dual general frames. In particular, we provide a sufficient condition for modal K4 algebras to be locally finite by identifying a structure which must be present in non-locally finite modal K4 algebras. We then show that this condition becomes both necessary and sufficient for σ-complete modal K4 algebras. Next, we translate this condition into a pair of order-theoretic conditions on transitive Kripke frames, providing a classification of local finiteness on their dual modal algebras. We further show that the logic of any class of well-founded transitive relations with no infinite antichains has the finite model property, and conclude that the logic of the class of well-quasi orderings has the finite model property.
ER -