Abstract

In a recent article, Alexander Kurz and Yde Venema establish a Lindström theorem for coalgebraic modal logic that is shown to imply a modal Lindström theorem by Maarten de Rijke. A later modal Lindström theorem has been established by Johan van Benthem, and this result still lacks a coalgebraic formulation. The main obstacle has so far been the lack of a suitable notion of ‘submodels’ in coalgebraic semantics, and the problem is left open by Kurz and Venema. In this article, we propose a solution to this problem and derive a general coalgebraic Lindström theorem along the lines of van Benthem's result. We provide several applications of the result.