This paper analyzes coalitions among self-interested agents that need to solve combinatorial optimization problems to operate e ciently in the world. By colluding (coordinating their actions by solving a joint optimization prob-lem) the agents can sometimes save costs compared to operating individually. A model of bounded rationality is adopted where computation resources are costly. It is not worthwhile solving the problems optimally: solution quality is decision-theoretically traded o against computation cost. A normative, application- and protocol-independent theory of coalitions among bounded-rational agents is devised. The optimal coalition structure and its stability are signi cantly a ected by the agents ' algorithms ' performance pro les and the cost of computation. This relationship is rst analyzed theoretically. Then a domain classi cation including rational and bounded-rational agents is in-troduced. Experimental results are presented in vehicle routing with real data from ve dispatch centers. This problem is NP-complete and the instances are so large that|with current technology|any agent's rationality is bounded by computational complexity. 1

A Dissertation Presented by TUOMAS W. SANDHOLM

In most real-world settings, due to limited time or other resources, an agent cannot perform all potentially useful deliberation and information gathering actions. This leads to the metareasoning problem of selecting such actions. Decision-theoretic methods for metareasoning have been studied in AI, but there are few theoretical results on the complexity of metareasoning. We derive hardness results for three settings which most real metareasoning systems would have to encompass as special cases. In the first, the agent has to decide how to allocate its deliberation time across anytime algorithms running on different problem instances. We show this to be N P-complete. In the second, the agent has to (dynamically) allocate its deliberation or information gathering resources across multiple actions that it has to choose among. We show this to be N P-hard even when evaluating each individual action is extremely simple. In the third, the agent has to (dynamically) choose a limited number of deliberation or information gathering actions to disambiguate the state of the world. We show that this is N P-hard under a natural restriction, and PSPACE-hard in general.

For information about citing this article, click here

Metaresoning is again under focus in the AI community. Here in this paper, a new classification for types of metareasoning has been proposed. In recent years, only the ones that are here named as pre-metareasoning and para-metareasoning have been studied. The first one is for predicting the best computation path for having better performance programs. The second, mostly known as interruptible anytime algorithm, is to limit the computation time externally when the approximate answer is better than nothing. One other type of metareasoning (called here as post-metareasoning) is discussed in a case study. It has been shown as an effective method for reducing error in self-localization. Based on the measurements in the case study, the post-metareasoning argued as useful when the effectiveness of reasoning methods are not known by the designer or when the system learns the reasoning methods and should evaluate and use the best one automatically. As the post-metareasoning is based on the results of different isolated reasoning methods, it is possible to be handled in parallel. The speed of post-metareasoning in such a case is determined by the time required by the slowest reasoning method and the post-metaresoning itself.

which attempts the interpretive understanding of social action in order thereby to arrive at a causal explanation of its course and effects. " Furthermore, "action is social when it takes account of the behaviour of others and is thereby orientated in its course " (Weber, 1947). Rational choice or action theory may be understood as one possible interpretation of Weber's program, though it must be said a rather special one in that it invites us to adopt the least complex conception of social action that we can analytically get away with in arriving at a "causal explanation of its course and effects. " It thus departs from many post-Weberian (and for that matter pre-Weberian) theoretical traditions- particularly those of a phenomenological persuasion- where the purpose seems to tilt in an entirely opposing direction, namely to find ways of conceiving (social) actions which are locally detailed and complex. Why it should be that rational choice theory adopts this heterodox standpoint will detain us below. Even with all its manifest limitations rational choice theory has arguably proven to

I am grateful for critical readings of this paper

“I believed in America” Earlier this year, the National Society of Film Critics, consisting of 57 of the leading film critics from the United States, issued a list of what they consider to be the most important movies produced during the 20 th century. As number one on their list they placed Francis Ford Coppola’s The Godfather (above such landmarks as Citizen Kane, Casablanca, Schindler’s List and Gone with the Wind). Among the many reasons for their choice, one must surely be that The Godfather illustrates something very important about our civilization. 1 It shows, maybe, what human existence has been like during this century; it examines family relations, immigration and multiculturalism, patriarchy, and the eternal questions about good and evil. There are countless ways in which The Godfather could be analyzed. But for me, The Godfather is above all a story about trust and distrust. Trust, says Piotr Sztompka, can be defined as “a bet on the future contingent actions of o (Sztompka 1998, p 20). When we put our trust in an individual or an institution, we are not completely convinced about what will happen (that would be “blind faith, ” which is different from trust). Even if we do not calculate the risks every time we decide whether or not to trust, absolute certainty would

Institutional change, collective action, and cooperation are closely related. The connection between institutional change and collective action comes from the fact that both democratic political institutions and norms of behavior are collectively chosen: they are the result of a collective action process. Collective action, however, requires a solution to the cooperation problem, for it is usually associated to the Prisoner’s Dilemma, which provides a formal representation of a ubiquitous type of situations that arises when individual interests undermine the collective welfare of the group. Essentially, the pessimistic result of this game is due to the fact that the players, who have a choice between cooperation and defection, prefer to defect, so the “cooperative ” strategy equilibrium (P,P) for the one-shot game is Pareto-dominated by (R, R) where the payoffs obey T>R>P>S. This paper suggests a theory of institutional change by advancing a theoretical alternative to escape from the non-cooperation trap. Keyword