Joseph U. Halpern

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In this chapter we relate epistemic logics with logics for strategic ability developed and studied in computer science, artificial intelligence and multi-agent systems. We discuss approaches from philosophy and artificial intelligence to modelling the interaction of agents’ knowledge and abilities and then focus on concurrent game models and the(More)
We argue that a notion of constrained time consistency is appropriate to evaluate the interim incentives to deviate from a plan in a decision problem with imperfect recall. Under perfect recall, constrained time consistency is equivalent to the standard notion of time consistency. It turns out that a behavioral strategy b is constrained time consistent if(More)
The Veterans Health Administration (VHA) is committed to continual refinement of its system of quality measurement. The VHA organizational structure for quality measurement has three levels. At the national level, the Associate Chief Medical Director for Quality Management provides leadership, sets policy, furnishes measurement tools, develops and(More)
Consider a very simple class of ( nite) games: after an initial move by nature, each player makes one move. Moreover, the players have common interests: at each node, all the players get the same payo . We show that the problem of determining whether there exists a joint strategy where each player has an expected payo of at least r is NP-complete as a(More)
The RFC Editor model described in this document divides the responsibilities for the RFC Series into three functions: the RFC Series Editor, the RFC Production Center, and the RFC Publisher. Internet Architecture Board (IAB) oversight via the RFC Series Oversight Committee (RSOC) is described, as is the relationship between the IETF Administrative Oversight(More)
When evaluating the rationality of a player in a game one has to examine counterfactuals such as “what would happen if the player were to do what he does not do?” In this paper I develop a model of a normal form game where counterfactuals of this sort are evaluated as in the philosophical literature (cf. Lewis, 1973; Stalnaker, 1968). According to this(More)
This paper gives a brief description of the telecommunications problems encountered when accessing medical data-bases. In the first part of the article, the authors described how the creation of a special telecommunications working group at IMA (the French MEDLINE Centre) helped to handle and solve these problems. The second part shows how French users will(More)
From my (admittedly very biased) point of view, perhaps the most significant event in the past year was the introduction of CoRR, the Computing Research Respository ( This is intended to be a central repository for the computing literature. It started in September 1998, and currently houses over 1500 papers. I hope(More)