In Twenty Problems in the Theory of Cellular Automata, Stephen Wolfram asks “how common computational universality and undecidability [are] in cellular automata.” This papers p...
We give a new proof showing that it is not possible to define in monadic second-order logic (MSO) a choice function on the infinite binary tree. This result was first obtained by G...
We analyze the multi-party contract-signing protocols of Garay and MacKenzie (GM) and of Baum and Waidner (BW). We use a finite-state tool, MOCHA, which allows specification of pr...
Abstract. Heuristic programming was the first area in which AI methods were tested. The favourite case-studies were fairly simple toyproblems, such as cryptarithmetic, games, such ...
Reasoning about program equivalence is one of the oldest problems in semantics. In recent years, useful techniques have been developed, based on bisimulations and logical relation...