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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal>INSTITUTE FOR ADVANCED STUDY<o:p></o:p></p><p class=MsoNormal>School of Mathematics<o:p></o:p></p><p class=MsoNormal>Princeton, NJ 08540<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><b>Theoretical Computer Science/Discrete Math Seminars<o:p></o:p></b></p><p class=MsoNormal><b>Week of March 4, 2019<o:p></o:p></b></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>--------------<o:p></o:p></p><p class=MsoNormal><span style='background:yellow;mso-highlight:yellow'>REMINDER: CSDM Seminars will be held in the West Building Lecture Hall</span> <o:p></o:p></p><p class=MsoNormal>--------------<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Monday, March 4<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Computer Science/Discrete Mathematics Seminar I<o:p></o:p></p><p class=MsoNormal>Topic: Local and global expansion of graphs<o:p></o:p></p><p class=MsoNormal>Speaker: Yuval Peled, New York University<o:p></o:p></p><p class=MsoNormal>Time/Room: 11:00am - 12:00pm/<b>West Building Lecture Hall</b><o:p></o:p></p><p class=MsoNormal><span lang=FR>Abstract Link: </span><a href="http://www.math.ias.edu/seminars/abstract?event=143187"><span lang=FR>http://www.math.ias.edu/seminars/abstract?event=143187</span></a><span lang=FR><o:p></o:p></span></p><p class=MsoNormal><span lang=FR><o:p> </o:p></span></p><p class=MsoNormal><span lang=FR><o:p> </o:p></span></p><p class=MsoNormal><span lang=FR><o:p> </o:p></span></p><p class=MsoNormal>Monday, March 4<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Seminar on Theoretical Machine Learning<o:p></o:p></p><p class=MsoNormal>Topic: FFJORD: Free-form Continuous Dynamics for Scalable Reversible Generative Models<o:p></o:p></p><p class=MsoNormal>Speaker: Will Grathwohl, University of Toronto<o:p></o:p></p><p class=MsoNormal>Time/Room: 12:15pm - 1:45pm/<b>Princeton University, CS 302</b><o:p></o:p></p><p class=MsoNormal><span lang=FR>Abstract Link: </span><a href="http://www.math.ias.edu/seminars/abstract?event=139487"><span lang=FR>http://www.math.ias.edu/seminars/abstract?event=139487</span></a><span lang=FR><o:p></o:p></span></p><p class=MsoNormal><span lang=FR><o:p> </o:p></span></p><p class=MsoNormal><span lang=FR><o:p> </o:p></span></p><p class=MsoNormal><span lang=FR><o:p> </o:p></span></p><p class=MsoNormal>Tuesday, March 5<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Computer Science/Discrete Mathematics Seminar II<o:p></o:p></p><p class=MsoNormal>Topic: Improved List-Decoding and Local List-Decoding Algorithms for Polynomial Codes<o:p></o:p></p><p class=MsoNormal>Speaker: Swastik Kopparty, Rutgers University; Member, School of Mathematics<o:p></o:p></p><p class=MsoNormal>Time/Room: 10:30am - 12:30pm/<b>West Building Lecture Hall</b><o:p></o:p></p><p class=MsoNormal><span lang=FR>Abstract Link: </span><a href="http://www.math.ias.edu/seminars/abstract?event=143190"><span lang=FR>http://www.math.ias.edu/seminars/abstract?event=143190</span></a><span lang=FR><o:p></o:p></span></p><p class=MsoNormal><span lang=FR><o:p> </o:p></span></p><p class=MsoNormal>1 Local and global expansion of graphs <br> Yuval Peled <br><br><br><o:p></o:p></p><p class=MsoNormal>The emerging theory of High-Dimensional Expansion suggests a number of inherently different notions to quantify expansion of simplicial complexes. We will talk about the notion of local spectral expansion, that plays a key role in recent advances in PCP theory, coding theory and counting complexity. Our focus is on bounded-degree complexes, where the problems can be stated in a graph-theoretic language: <br><br>Let $G$ be a graph. For a vertex $v \in G$, we denote by $G_v$ the subgraph of $G $ that is induced by the neighbors of $v$. We say that $G$ is $(a,b)$-regular if (I) $G$ is $a$-regular and (II) $G_v$ is $b$-regular for every vertex $v$. We analyse the spectral expansion of $(a,b)$-regular graphs: <br><br>What is the largest spectral gap in the adjacency operator of an $(a,b)$-regular graph $G$? What is the relation between the local expansion of the graphs ${G_v : v \in G}$ and the global expansion of $G$? We will also present a new construction of $(a,b)$-regular local-and-global expanders. <br><br>Joint work with Michael Chapman and Nati Linial.<o:p></o:p></p><p class=MsoNormal><a href="http://www.math.ias.edu/seminars/abstract?event=143187">http://www.math.ias.edu/seminars/abstract?event=143187</a><br><br>2 FFJORD: Free-form Continuous Dynamics for Scalable Reversible Generative Models <br> Will Grathwohl <br><br><br><o:p></o:p></p><p class=MsoNormal>A promising class of generative models maps points from a simple distribution to a complex distribution through an invertible neural network. Likelihood-based training of these models requires restricting their architectures to allow cheap computation of Jacobian determinants. Alternatively, the Jacobian trace can be used if the transformation is specified by an ordinary differential equation. In this paper, we use Hutchinson's trace estimator to give a scalable unbiased estimate of the log-density. The result is a continuous-time invertible generative model with unbiased density estimation and one-pass sampling, while allowing unrestricted neural network architectures. We demonstrate our approach on high-dimensional density estimation, image generation, and variational inference, achieving the state-of-the-art among exact likelihood methods with efficient sampling.<o:p></o:p></p><p class=MsoNormal><a href="http://www.math.ias.edu/seminars/abstract?event=139487">http://www.math.ias.edu/seminars/abstract?event=139487</a><br><br>3 Improved List-Decoding and Local List-Decoding Algorithms for Polynomial Codes <br> Swastik Kopparty <br><br><br><o:p></o:p></p><p class=MsoNormal>I will talk about a recent result showing that some well-studied polynomial-based error-correcting codes (Folded Reed-Solomon Codes and Multiplicity Codes) are "list-decodable upto capacity with constant list-size". <br><br>At its core, this is a statement about questions of the form: "Given some points in the plane, how many low degree univariate polynomials are such that their graphs pass through 10% of these points"? <br><br>This leads to list-decodable and locally list-decodable error-correcting codes with the best known parameters. <br><br>Based on joint work with Noga Ron-Zewi, Shubhangi Saraf and Mary Wootters.<o:p></o:p></p><p class=MsoNormal><a href="http://www.math.ias.edu/seminars/abstract?event=143190">http://www.math.ias.edu/seminars/abstract?event=143190</a><br><br>Computer Science/Discrete Math Seminars can be found on our web page:<br><br><a href="http://www.math.ias.edu/csdm">http://www.math.ias.edu/csdm</a><br><a href="http://www.math.ias.edu">http://www.math.ias.edu</a><o:p></o:p></p></div></body></html>