In this paper we demonstrate decidability for the intuitionistic modal logic S4 first formulated
by Fischer Servi. This solves a problem that has been open for almost thirty years since it …

In this article, we perform a detailed proof theoretic investigation of a wide number of
relevant logics by employing the well-established methodology of labelled sequent calculi to …

We introduce FIK, a natural intuitionistic modal logic specified by Kripke models satisfying
the condition of forward confluence. We give a complete Hilbert-style axiomatization of this …

We define a family of propositional constructive modal logics corresponding each to a
different classical modal system. The logics are defined in the style of Wijesekera's …

This paper gives a broad account of the various sequent-based proof formalisms in the proof-
theoretic literature. We consider formalisms for various modal and tense logics, intuitionistic …

This paper challenges the negative attitudes towards labelled proof systems, usually
referred to as semantic pollution, by arguing that such critiques overlook the full potential of …

The discussion about how to put together Gentzen's systems for classical and intuitionistic
logic in a single unified system is back in fashion. Indeed, recently Prawitz and others have …

In this paper, we present an algorithm for establishing decidability and finite model property
of intuitionistic modal logic IK. These two results have been previously established …

Whilst mathematicians assume classical reasoning principles by default they often context
switch when working, restricting themselves to various forms of subclassical reasoning. This …

Extending sequent calculus with further structure or language has been a fruitful approach in
structural proof theory for finding different cut-free complete proof systems. Finding …