<div dir="ltr"><div dir="ltr"><div class="gmail_default" style="font-size:small"><div class="gmail_default"><p style="font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;margin:0px"><font face="arial, sans-serif"><font style="vertical-align:inherit"><font style="vertical-align:inherit"><b>When:</b> </font></font><font style="vertical-align:inherit"><font style="vertical-align:inherit"> Friday, January 8th at 11:10 am CT</font></font><br></font></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font face="arial, sans-serif"> </font></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font face="arial, sans-serif"><font style="vertical-align:inherit"><font style="vertical-align:inherit"><b>Where:</b> </font></font></font><font color="#000000" style="font-family:arial,sans-serif">Zoom Virtual Talk (</font><b style="font-family:arial,sans-serif"><font color="#0000ff"><a href="https://uchicagogroup.zoom.us/webinar/register/WN_3DqSDK9uT9qD71bj-g0LUw" target="_blank">register in advance here</a></font></b><font color="#000000" style="font-family:arial,sans-serif">)</font></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font face="arial, sans-serif"> </font></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font face="arial, sans-serif"><font style="vertical-align:inherit"><font style="vertical-align:inherit"><b>Who: </b> </font></font></font>Frederic Koehler, MIT</p></div><div class="gmail_default"><br></div><div class="gmail_default"><br></div><div class="gmail_default"><div><b>Title: <font face="arial, sans-serif"> </font></b><font face="arial, sans-serif"><span style="color:rgb(85,85,85)">Learning Some </span><span style="color:rgb(85,85,85)">Ill</span><span style="color:rgb(85,85,85)">-</span><span style="color:rgb(85,85,85)">Conditioned</span><span style="color:rgb(85,85,85)"> Gaussian Graphical Models</span> </font><br><br><b>Abstract: </b>Gaussian Graphical models have wide-ranging applications in machine learning and the natural and social sciences where they are one of the most popular ways to model statistical relationships between observed variables. In most of the settings in which they are applied, the number of observed samples is much smaller than the dimension and the goal is to learn the model assuming the underlying model is sparse. While there are a variety of algorithms (e.g. Graphical Lasso, CLIME) that provably recover the graph structure with a logarithmic number of samples, they all require that the precision matrix is in some way well-conditioned. Here we give the first fixed polynomial-time algorithms for learning attractive GGMs and walk-summable GGMs with a logarithmic number of samples and without any such assumptions. In particular, our algorithms can tolerate strong dependencies among the variables. We complement our results with experiments showing that many existing algorithms fail even in some simple settings where there are long dependency chains. Joint work with Jon Kelner, Raghu Meka, and Ankur Moitra.</div><div><br></div><div><font face="arial, sans-serif"><b>Bio:</b> Frederic Koehler is a fifth year PHD Candidate at MIT in the Department of Mathematics, where he is jointly advised by Professors Ankur Moitra and Elchanan Mossel. His research focuses on theoretical machine learning, algorithmic statistics, and related areas.</font><div><div style="line-height:22px;color:rgb(102,102,102);font-style:italic"></div></div><div><br></div></div><div><b>Host: </b><a href="mailto:madhurt@ttic.edu" target="_blank">Madhur Tulsiani</a><br></div><div><br></div><div><br></div><div><br></div><div><br></div></div></div><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><font face="arial, helvetica, sans-serif">Mary C. Marre</font><div><font face="arial, helvetica, sans-serif">Faculty Administrative Support</font></div><div><i><font face="arial, helvetica, sans-serif" color="#3d85c6"><b>Toyota Technological Institute</b></font></i></div><div><i><font face="arial, helvetica, sans-serif" color="#3d85c6">6045 S. Kenwood Avenue</font></i></div><div><i><font face="arial, helvetica, sans-serif" color="#3d85c6">Room 517</font></i></div><div><i><font face="arial, helvetica, sans-serif" color="#3d85c6">Chicago, IL 60637</font></i></div><div><i><font face="arial, helvetica, sans-serif">p:(773) 834-1757</font></i></div><div><i><font face="arial, helvetica, sans-serif">f: (773) 357-6970</font></i></div><div><b><i><a href="mailto:mmarre@ttic.edu" target="_blank"><font face="arial, helvetica, sans-serif">mmarre@ttic.edu</font></a></i></b></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Jan 7, 2021 at 2:45 PM Mary Marre <<a href="mailto:mmarre@ttic.edu">mmarre@ttic.edu</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div dir="ltr"><div><div style="font-size:small"><p style="font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;margin:0px"><font face="arial, sans-serif"><font style="vertical-align:inherit"><font style="vertical-align:inherit"><b>When:</b> </font></font><font style="vertical-align:inherit"><font style="vertical-align:inherit"> Friday, January 8th at 11:10 am CT</font></font><br></font></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font face="arial, sans-serif"> </font></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font face="arial, sans-serif"><font style="vertical-align:inherit"><font style="vertical-align:inherit"><b>Where:</b> </font></font></font><font color="#000000" style="font-family:arial,sans-serif">Zoom Virtual Talk (</font><b style="font-family:arial,sans-serif"><font color="#0000ff"><a href="https://uchicagogroup.zoom.us/webinar/register/WN_3DqSDK9uT9qD71bj-g0LUw" target="_blank">register in advance here</a></font></b><font color="#000000" style="font-family:arial,sans-serif">)</font></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font face="arial, sans-serif"> </font></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font face="arial, sans-serif"><font style="vertical-align:inherit"><font style="vertical-align:inherit"><b>Who: </b> </font></font></font>Frederic Koehler, MIT</p></div><div style="font-size:small"><br></div><div style="font-size:small"><br></div><div><div style="font-size:small"><b>Title: <font face="arial, sans-serif"> </font></b><font face="arial, sans-serif"><span style="color:rgb(85,85,85)">Learning Some </span><span style="color:rgb(85,85,85)">Ill</span><span style="color:rgb(85,85,85)">-</span><span style="color:rgb(85,85,85)">Conditioned</span><span style="color:rgb(85,85,85)"> Gaussian Graphical Models</span> </font><br><br><b>Abstract: </b>Gaussian Graphical models have wide-ranging applications in machine learning and the natural and social sciences where they are one of the most popular ways to model statistical relationships between observed variables. In most of the settings in which they are applied, the number of observed samples is much smaller than the dimension and the goal is to learn the model assuming the underlying model is sparse. While there are a variety of algorithms (e.g. Graphical Lasso, CLIME) that provably recover the graph structure with a logarithmic number of samples, they all require that the precision matrix is in some way well-conditioned. Here we give the first fixed polynomial-time algorithms for learning attractive GGMs and walk-summable GGMs with a logarithmic number of samples and without any such assumptions. In particular, our algorithms can tolerate strong dependencies among the variables. We complement our results with experiments showing that many existing algorithms fail even in some simple settings where there are long dependency chains. Joint work with Jon Kelner, Raghu Meka, and Ankur Moitra.</div><div style="font-size:small"><br></div><div><font face="arial, sans-serif"><b>Bio:</b> Frederic Koehler is a fifth year PHD Candidate at MIT in the Department of Mathematics, where he is jointly advised by Professors Ankur Moitra and Elchanan Mossel. His research focuses on theoretical machine learning, algorithmic statistics, and related areas.</font><div><div style="line-height:22px;color:rgb(102,102,102);font-style:italic"></div></div><div style="font-size:small"><br></div></div><div style="font-size:small"><b>Host: </b><a href="mailto:madhurt@ttic.edu" target="_blank">Madhur Tulsiani</a><br></div><div style="font-size:small"><br></div><div style="font-size:small"><br></div></div></div><div><div dir="ltr"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><font face="arial, helvetica, sans-serif">Mary C. Marre</font><div><font face="arial, helvetica, sans-serif">Faculty Administrative Support</font></div><div><i><font face="arial, helvetica, sans-serif" color="#3d85c6"><b>Toyota Technological Institute</b></font></i></div><div><i><font face="arial, helvetica, sans-serif" color="#3d85c6">6045 S. Kenwood Avenue</font></i></div><div><i><font face="arial, helvetica, sans-serif" color="#3d85c6">Room 517</font></i></div><div><i><font face="arial, helvetica, sans-serif" color="#3d85c6">Chicago, IL 60637</font></i></div><div><i><font face="arial, helvetica, sans-serif">p:(773) 834-1757</font></i></div><div><i><font face="arial, helvetica, sans-serif">f: (773) 357-6970</font></i></div><div><b><i><a href="mailto:mmarre@ttic.edu" target="_blank"><font face="arial, helvetica, sans-serif">mmarre@ttic.edu</font></a></i></b></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Jan 1, 2021 at 4:57 PM Mary Marre <<a href="mailto:mmarre@ttic.edu" target="_blank">mmarre@ttic.edu</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div style="font-size:small"><div style="padding:20px 0px 0px;font-size:0.875rem"><table cellpadding="0" style="border-collapse:collapse;margin-top:0px;width:auto;font-family:Roboto,RobotoDraft,Helvetica,Arial,sans-serif;font-size:0.875rem;letter-spacing:0.2px;display:block"><tbody style="display:block"><tr style="height:auto;display:flex"><td colspan="3"></td></tr></tbody></table></div><div id="gmail-m_9171473982252258149m_-959809998662976271gmail-m_8462555415993001975m_-2429055123417201446gmail-:265"><div></div><div></div><div></div><div></div></div><div><div></div><div id="gmail-m_9171473982252258149m_-959809998662976271gmail-m_8462555415993001975m_-2429055123417201446gmail-:25s"></div><div id="gmail-m_9171473982252258149m_-959809998662976271gmail-m_8462555415993001975m_-2429055123417201446gmail-:263" style="font-size:0.875rem;direction:ltr;margin:8px 0px 0px;padding:0px"><div id="gmail-m_9171473982252258149m_-959809998662976271gmail-m_8462555415993001975m_-2429055123417201446gmail-:264" style="overflow:hidden;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:small;line-height:1.5"><div dir="ltr"><div dir="ltr"><div><div><p style="font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:normal;margin:0px"><font face="arial, sans-serif"><font style="vertical-align:inherit"><font style="vertical-align:inherit"><b>When:</b> </font></font><font style="vertical-align:inherit"><font style="vertical-align:inherit"> Friday, January 8th at 11:10 am CT</font></font><br></font></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font face="arial, sans-serif"> </font></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font face="arial, sans-serif"><font style="vertical-align:inherit"><font style="vertical-align:inherit"><b>Where:</b> </font></font></font><font color="#000000" style="font-family:arial,sans-serif">Zoom Virtual Talk (</font><b style="font-family:arial,sans-serif"><font color="#0000ff"><a href="https://uchicagogroup.zoom.us/webinar/register/WN_3DqSDK9uT9qD71bj-g0LUw" target="_blank">register in advance here</a></font></b><font color="#000000" style="font-family:arial,sans-serif">)</font></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font face="arial, sans-serif"> </font></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font face="arial, sans-serif"><font style="vertical-align:inherit"><font style="vertical-align:inherit"><b>Who: </b> </font></font></font>Frederic Koehler, MIT</p></div><div><br></div><div><br></div><div><div><b>Title: <font face="arial, sans-serif"> </font></b><font face="arial, sans-serif"><span style="color:rgb(85,85,85)">Learning Some </span><span style="color:rgb(85,85,85)">Ill</span><span style="color:rgb(85,85,85)">-</span><span style="color:rgb(85,85,85)">Conditioned</span><span style="color:rgb(85,85,85)"> Gaussian Graphical Models</span> <br></font><br><b>Abstract: </b>Gaussian Graphical models have wide-ranging applications in machine learning and the natural and social sciences where they are one of the most popular ways to model statistical relationships between observed variables. In most of the settings in which they are applied, the number of observed samples is much smaller than the dimension and the goal is to learn the model assuming the underlying model is sparse. While there are a variety of algorithms (e.g. Graphical Lasso, CLIME) that provably recover the graph structure with a logarithmic number of samples, they all require that the precision matrix is in some way well-conditioned. Here we give the first fixed polynomial-time algorithms for learning attractive GGMs and walk-summable GGMs with a logarithmic number of samples and without any such assumptions. In particular, our algorithms can tolerate strong dependencies among the variables. We complement our results with experiments showing that many existing algorithms fail even in some simple settings where there are long dependency chains. Joint work with Jon Kelner, Raghu Meka, and Ankur Moitra.<div><div style="line-height:22px;color:rgb(102,102,102);font-style:italic;font-family:Arial,"Helvetica Neue",Helvetica,sans-serif"></div></div><div><br></div></div><div><b>Host: </b><a href="mailto:madhurt@ttic.edu" target="_blank">Madhur Tulsiani</a><br></div><div><br></div><div><br></div><div><br></div></div></div></div></div></div></div></div></div><div><div dir="ltr"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><font face="arial, helvetica, sans-serif">Mary C. Marre</font><div><font face="arial, helvetica, sans-serif">Faculty Administrative Support</font></div><div><i><font face="arial, helvetica, sans-serif" color="#3d85c6"><b>Toyota Technological Institute</b></font></i></div><div><i><font face="arial, helvetica, sans-serif" color="#3d85c6">6045 S. Kenwood Avenue</font></i></div><div><i><font face="arial, helvetica, sans-serif" color="#3d85c6">Room 517</font></i></div><div><i><font face="arial, helvetica, sans-serif" color="#3d85c6">Chicago, IL 60637</font></i></div><div><i><font face="arial, helvetica, sans-serif">p:(773) 834-1757</font></i></div><div><i><font face="arial, helvetica, sans-serif">f: (773) 357-6970</font></i></div><div><b><i><a href="mailto:mmarre@ttic.edu" target="_blank"><font face="arial, helvetica, sans-serif">mmarre@ttic.edu</font></a></i></b></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div>
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