Reducing Modal Consequence Relations
Marcus Kracht · Journal of Logic and Computation · 2001
In this paper we investigate the possibility of reducing derivability in a modal consequence relation to consistency in unimodal and polymodal K by means of so‐called reduction functions. We present new and easy methods to prove standard results on decidability, complexity, finite model property, interpolation and Halldén‐completeness using only the reduction functions. Some new results on complexity of modal logics will be established. All proofs are in addition constructive.