A Formal Separation Between Strategic and Nonstrategic Behavior

It is common in multiagent systems to make a distinction between "strategic" behavior and other forms of intentional but "nonstrategic" behavior: typically, that strategic agents model other agents while nonstrategic agents do not. However, a crisp boundary between these concepts has proven elusive. This problem is pervasive throughout the game theoretic literature on bounded rationality and particularly critical in parts of the behavioral game theory literature that make an explicit distinction between the behavior of "nonstrategic" level-0 agents and "strategic" higher-level agents (e.g., the level-k and cognitive hierarchy models). Overall, work discussing bounded rationality rarely gives clear guidance on how the rationality of nonstrategic agents must be bounded, instead typically just singling out specific decision rules and informally asserting them to be nonstrategic (e.g., truthfully revealing private information; randomizing uniformly). In this work, we propose a new, formal characterization of nonstrategic behavior. Our main contribution is to show that it satisfies two properties: (1) it is general enough to capture all purportedly "nonstrategic" decision rules of which we are aware in the behavioral game theory literature; (2) behavior that obeys our characterization is distinct from strategic behavior in a precise sense

Polynomial-time Computation of Exact Correlated Equilibrium in Compact Games

In a landmark paper, Papadimitriou and Roughgarden described a polynomial-time algorithm ("Ellipsoid Against Hope") for computing sample correlated equilibria of concisely-represented games. Recently, Stein, Parrilo and Ozdaglar showed that this algorithm can fail to find an exact correlated equilibrium, but can be easily modified to efficiently compute approximate correlated equilibria. Currently, it remains unresolved whether the algorithm can be modified to compute an exact correlated equilibrium. We show that it can, presenting a variant of the Ellipsoid Against Hope algorithm that guarantees the polynomial-time identification of exact correlated equilibrium. Our new algorithm differs from the original primarily in its use of a separation oracle that produces cuts corresponding to pure-strategy profiles. As a result, we no longer face the numerical precision issues encountered by the original approach, and both the resulting algorithm and its analysis are considerably simplified. Our new separation oracle can be understood as a derandomization of Papadimitriou and Roughgarden's original separation oracle via the method of conditional probabilities. Also, the equilibria returned by our algorithm are distributions with polynomial-sized supports, which are simpler (in the sense of being representable in fewer bits) than the mixtures of product distributions produced previously; no tractable algorithm has previously been proposed for identifying such equilibria.Comment: 15 page

Review of \u3ci\u3eSwords and Ploughshares: War and Agriculture in Western Canada\u3c/i\u3e by R. C. Macleod

The title of this collection of articles may suggest to some readers that its subject, in the tradition of John Thompson\u27s Harvests of War, is the impact of war on prairie agriculture. This is not the case, though, since the articles are not confined to prairie subjects and since most of them are not directly related to both war and agriculture -indeed, some have only a tenuous connection with either. However, what this rather oddly matched collection lacks in focus it makes up in other ways, presenting a number of pieces which address important issues and which deserve a wide readership

The Poison Porridge Case: Chinese and the Administration of Justice In Early Saskatchewan

On the morning of 8 August 1907 a number of patrons were taking breakfast in the Capital Restaurant on Lome Street in Regina. The restaurant had not been in operation long but was apparently doing a good business, so it must have been somewhat disturbing to Mr. Steele, the owner and manager, when shortly after beginning their morning meal a number of his patrons became ill. The symptoms included quite severe abdominal pains so the decision was taken to send for a doctor who arrived to find nine people suffering from what was obviously something rather more serious than indigestion. In fact, he soon identified the symptoms as resulting from some sort of poisoning. He provided what treatment he could to those who were ill and sent the three worst cases to the local hospital. He then examined the food they had been eating and identified the oatmeal served that morning as the source of the poison. Under these circumstances it seemed wise to summon the police