Best-response sets (Pearce [29, 1984]) characterize the epistemic condition of “rationality and common belief of rationality.” When rationality incorporates a weak-dominance (admissibility) requirement, the self-admissible set (SAS) concept (Brandenburger-Friedenberg-Keisler [18, 2008]) characterizes “rationality and common assumption of rationality.” We analyze the behavior of SAS’s in some ga...

In this article we address the issue of con dentiality of information in the context of downgrading systems i.e. systems admitting information ow between secrecy levels only through a downgrader. Inspired by the intuition underlying the usual de nition of admissible information ow, we propose an analogue based on trace equivalence as developed in the context of concurrency theory and on a modi ...

As partial justification of their framework for iterated belief revision Darwiche and Pearl convincingly argued against Boutilier’s natural revision and provided a prototypical revision operator that fits into their scheme. We show that the Darwiche-Pearl arguments lead naturally to the acceptance of a smaller class of operators which we refer to as admissible. Admissible revision ensures that ...

We investigate the computational complexity of deciding whether a given inference rule is admissible for some modal and superintuitionistic logics. We state a broad condition under which the admissibility problem is coNEXP -hard. We also show that admissibility in several well-known systems (including GL, S4, and IPC ) is in coNE , thus obtaining a sharp complexity estimate for admissibility in...

We develop a criterion for coalition formation among goal-directed agents, the indecomposable do-ut-des property. The indecomposable do-ut-des property refines the do-ut-des property (literally give to get) by considering the fact that agents prefer to form coalitions whose components cannot be formed independently. A formal description of this property is provided as well as an analysis of alg...

We examine a special case of admissible representations of the closed interval, namely those which arise via sequences of a finite number of Möbius transformations. We regard certain sets of Möbius transformations as a generalized notion of digits and introduce sufficient conditions that such a “digit set” yields an admissible representation of [0,+∞]. Furthermore we establish the productivity ...

This paper contains a proof–theoretic account of unification in intermediate logics. It is shown that many existing results can be extended to fragments that at least contain implication and conjunction. For such fragments, the connection between valuations and most general unifiers is clarified, and it is shown how from the closure of a formula under the Visser rules a proof of the formula und...

2 . Admissible constellations . Let us start with a formal definition : al, 122, . . ., ak is an admissible sequence of integers if the ai's do notform a complete set of residues mod p for any prime p.-Clearly only the primes p 5 k have to be considered . A sequence which is not admissible is called inadmissible . Beginning with the admissible sequence (ai) we now search for constellations of i...