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CMU-CS-02-104
Computer Science Department
School of Computer Science, Carnegie Mellon University
CMU-CS-02-104
Existence of Multiagent Equilibria with Limited Agents
Michael Bowling, Manuela Veloso
January 2002
CMU-CS-02-104.ps
CMU-CS-02-104.pdf
Keywords: Multiagent learning, reinforcement learning,
multiagent systems, slimited agents, Nash equilibria
Multiagent learning is a neccessary yet challenging problem as
multiagent systems become more prevalent and environments become more
dynamic. Much of the groundbreaking work in this area draws on
notable results from the game theory community. Nash Equilibria, in
particular, is a very important concept to multiagent learning.
Learners that directly learn equilibria obviously rely on their
existence. Learners that instead seek to play optimally with respect
to the other players also depend upon equilibria since equilibria are,
and are the only, learning fixed points. From another perspective,
agents with limitations are real and common, both agents with
undesired physical limitations as well as self-imposed rational
limitations. This paper explores the interactions of these two
important concepts, examining whether equilibria continue to exist
when agents have limitations. We look at the general effects
limitations can have on agent behavior, and define a natural extention
of equilibria that accounts for these limitations. We show that
existence cannot be guaranteed in general, but prove existence under
certain classes of domains and agent limitations. These results have
wide applicability as they are not tied to any particular learning
algorithm or specific instance of agent limtations. We then present
empirical results from a specific multiagent learner applied to a
specific instance of limited agents. These results demonstrate that
learning with limitations is possible, and our theoretical analysis of
equilibria under limitations is relevant.
17 pages
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