We study many-valued coalgebraic logics with semi-primal algebras of truth-degrees. We provide a systematic way to lift endofunctors defined on the variety of Boolean algebras to endofunctors on the variety generated by a semi-primal algebra. We show that this can be extended to a technique to lift classical coalgebraic logics to many-valued ones, and that (one-step) completeness and expressivity are preserved under this lifting. For specific classes of endofunctors, we also describe how to obtain an axiomatization of the lifted many-valued logic directly from an axiomatization of the original classical one. In particular, we apply all of these techniques to classical modal logic.

@article{paperbot2743,
  title = {Many-valued coalgebraic logic over semi-primal varieties},
  author = {Alexander Kurz and Wolfgang Poiger and Bruno Teheux},
  journal = {Logical Methods in Computer Science},
  volume = {Volume 20, Issue 3},
  year = {2024},
  doi = {10.46298/lmcs-20(3:6)2024}
}