Approximation Algorithms for Partially Colorable Graphs

Graph coloring problems are a central topic of study in the theory of algorithms. We study the problem of partially coloring partially colorable graphs. For alpha = alpha |V| such that the graph induced on S is k-colorable. Partial k-colorability is a more robust structural property of a graph than k-colorability. For graphs that arise in practice, partial k-colorability might be a better notion to use than k-colorability, since data arising in practice often contains various forms of noise. We give a polynomial time algorithm that takes as input a (1 - epsilon)-partially 3-colorable graph G and a constant gamma in [epsilon, 1/10], and colors a (1 - epsilon/gamma) fraction of the vertices using O~(n^{0.25 + O(gamma^{1/2})}) colors. We also study natural semi-random families of instances of partially 3-colorable graphs and partially 2-colorable graphs, and give stronger bi-criteria approximation guarantees for these family of instances

End of an Era: Two Linfield Legends Step Down

It is the end of an era with the retirement of Ken Ericksen, professor of English, after 45 years, and Dave Hansen, who is stepping down as dean of students after 22 years and returning to the classroom

Hirota derivatives and representation theory

It is shown that the Hirota derivative can be used to construct the plethysm for tensor products of representations of {sl}_2(k)

Time-Varying Volatility and the Dynamic Behavior of the Term Structure

In this paper, we consider a framework with which the cross sectional and time series behavior of the yield curve can be studied simultaneously. We examine the relationship between the yield curve and the time-varying conditional volatility of the Treasury bill market. We demonstrate that differently shaped yield curves can result given different combinations of volatility and expectations about future spot rates. Moreover, adjusting the forward rate for the volatility related liquidity premium can improve its performance as a predictor of future spot rates at least for the period from August 1964 to August 1979.

Cheol Woong Kim, In Search of Freedom, An Evening of Music and Conversation, October 8, 2008

This is the concert program of the In Search of Freedom, An Evening of Music and Conversation performance on Wednesday, October 8, 2008 at 7:30 p.m., at the Tsai Performance Center, 685 Commonwealth Avenue, Boston, Massachusetts. Works performed were Nocturne in C sharp minor, Op. Posth by Frédéric Chopin, Piano Concerto No. 21 in C Major, K. 467 "Elvira Madigan" by Wolfgang Amadé Mozart, Chosun is One by Dong Choon Sung, Voices Yet Unheard by Sung Eun Han-Andersen, and Arirang Sonata and In Search of Freedom by Cheol Woong Kim. Digitization for Boston University Concert Programs was supported by the Boston University Center for the Humanities Library Endowed Fund

Sufficient condition on noise correlations for scalable quantum computing

I study the effectiveness of fault-tolerant quantum computation against correlated Hamiltonian noise, and derive a sufficient condition for scalability. Arbitrarily long quantum computations can be executed reliably provided that noise terms acting collectively on k system qubits are sufficiently weak, and decay sufficiently rapidly with increasing k and with increasing spatial separation of the qubits.Comment: 13 pages, 1 figure. (v2) Minor corrections and clarification