We give an evolving algebra solution for the well-known railroad crossing problem and use the occasion to experiment with agents that perform instantaneous actions in continuous t...
We survey two basic techniques for showing that the monadic second-order theory of a structure is decidable. In the first approach, one deals with finite fragments of the theory (g...
We describe the formalisation of the normal forms of context-free grammars (CFGs) using the HOL4 theorem prover. These straightforward pen and paper proofs easily understood from t...
Abstract. This paper shows undecidability of type-checking and typeinference problems in domain-free typed lambda-calculi with existential types: a negation and conjunction fragmen...
Koji Nakazawa, Makoto Tatsuta, Yukiyoshi Kameyama,...
Model-checking problems for PDL (propositional dynamic logic) and its extension PDL (which includes the intersection operator on programs) over various classes of infinite state sy...