14,524 research outputs found
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
John Wesley and the Christian ministry: the sources and development of his options and practice
Not availabl
Experimentally Accessible Witnesses of Many-Body Localization
The phenomenon of many-body localized (MBL) systems has attracted significant interest in recent years, for its intriguing implications from a perspective of both condensed-matter and statistical physics: they are insulators even at non-zero temperature and fail to thermalize, violating expectations from quantum statistical mechanics. What is more, recent seminal experimental developments with ultra-cold atoms in optical lattices constituting analog quantum simulators have pushed many-body localized systems into the realm of physical systems that can be measured with high accuracy. In this work, we introduce experimentally accessible witnesses that directly probe distinct features of MBL, distinguishing it from its Anderson counterpart. We insist on building our toolbox from techniques available in the laboratory, including on-site addressing, super-lattices, and time-of-flight measurements, identifying witnesses based on fluctuations, density–density correlators, densities, and entanglement. We build upon the theory of out of equilibrium quantum systems, in conjunction with tensor network and exact simulations, showing the effectiveness of the tools for realistic models
A Study of Dropouts from Continuation High School in Spokane from September, 1967, to November, 1968
The purpose of this study was to identify the characteristics of students who dropped out of Spokane Continuation High School. A great deal has been written on the subject of dropouts, and as part of this study the writer reviewed and reported on the most current material available
I Used To Love You But It\u27s All Over Now
https://digitalcommons.library.umaine.edu/mmb-vp/1902/thumbnail.jp
Wait Till You Get Them Up In The Air, Boys
https://digitalcommons.library.umaine.edu/mmb-vp/2611/thumbnail.jp
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