<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<style type="text/css" style="display:none;"> P {margin-top:0;margin-bottom:0;} </style>
</head>
<body dir="ltr">
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<div style="margin:0px;font-size:15px;font-family:"Segoe UI", "Segoe UI Web (West European)", "Segoe UI", -apple-system, "system-ui", Roboto, "Helvetica Neue", sans-serif;color:rgb(32, 31, 30);background-color:rgb(255, 255, 255)">
<div style="margin:0px"><span style="margin:0px;font-size:16px;color:rgb(49, 49, 49);word-spacing:1px"><font style="font-size:1.125rem"><b>Date:</b> March 2nd, Wednesday</font></span></div>
<div style="margin:0px">
<div style="margin:0px;font-size:16px;color:rgb(49, 49, 49);word-spacing:1px"><font style="font-size:1.125rem"><b>Time: </b>12:30pm CT</font></div>
<div style="margin:0px;font-size:16px;color:rgb(49, 49, 49);word-spacing:1px"><font style="font-size:1.125rem"><b>Location: </b>JCL 390</font></div>
<div dir="auto" style="margin:0px;font-size:16px;color:rgb(49, 49, 49);word-spacing:1px">
<b><font style="font-size:1.125rem"><br>
</font></b></div>
<div dir="auto" style="margin:0px;font-size:16px;color:rgb(49, 49, 49);word-spacing:1px">
<b><font style="font-size:1.125rem">Speaker: Max Ovsiankin</font></b></div>
<div dir="auto" style="margin:0px;font-size:16px;color:rgb(49, 49, 49);word-spacing:1px">
<font size="4"><br>
</font></div>
<b style="font-size:16px;word-spacing:1px;color:rgb(49, 49, 49)"><font style="font-size:1.125rem">Title: </font></b><font size="4">Streaming Algorithms for Ellipsoidal Approximation of Convex Polytopes</font></div>
<div style="margin:0px"><b style="font-size:16px;word-spacing:1px;color:rgb(49, 49, 49)"><font style="font-size:1.125rem"><br>
</font></b></div>
<div style="margin:0px"><span style="margin:0px;font-size:16px;color:rgb(49, 49, 49);word-spacing:1px"><font style="font-size:1.125rem"><b>Zoom: </b>[<a href="https://www.google.com/url?q=https%3A%2F%2Fuchicago.zoom.us%2Fj%2F97375149992%3Fpwd%3DYmNGa1FoaW1WOXVaQ1UxcVBWMjhVdz09&sa=D&ust=1646512430502000&usg=AOvVaw13FTypdW6t1Zcb49FcCVaI" title="https://www.google.com/url?q=https%3A%2F%2Fuchicago.zoom.us%2Fj%2F97375149992%3Fpwd%3DYmNGa1FoaW1WOXVaQ1UxcVBWMjhVdz09&sa=D&ust=1646512430502000&usg=AOvVaw13FTypdW6t1Zcb49FcCVaI">link</a>]</font></span></div>
<div style="margin:0px"><br>
</div>
<div style="margin:0px">
<div dir="auto" style="margin:0px"><font style="color:rgb(49, 49, 49);font-size:1.125rem;word-spacing:1px"><b>Abstract: </b>John's theorem is a useful result that says that any symmetric convex body can be well-approximated by some ellipsoid with an approximation
factor that is the square root of the dimension of the body. Ellipsoidal approximations more generally have been applied to approximating the volume of convex bodies and sampling from them using Markov chains, and have been applied in other areas such as online
optimization. We present new streaming algorithms for finding ellipsoidal approximations when these convex bodies are polytopes. These algorithms are well-suited to low-memory or online settings, and their runtime matches that of the best known algorithms
for the offline setting. The approximation factor differs from the offline solution only by a factor sub-logarithmic in the aspect ratio of the polytope. Based on joint work with Naren Manoj and Yury Makarychev.</font></div>
</div>
</div>
<div style="margin:0px;font-size:15px;font-family:"Segoe UI", "Segoe UI Web (West European)", "Segoe UI", -apple-system, "system-ui", Roboto, "Helvetica Neue", sans-serif;color:rgb(32, 31, 30);background-color:rgb(255, 255, 255)">
<font size="4"><br>
</font></div>
<div style="margin:0px;font-size:15px;font-family:"Segoe UI", "Segoe UI Web (West European)", "Segoe UI", -apple-system, "system-ui", Roboto, "Helvetica Neue", sans-serif;color:rgb(32, 31, 30);background-color:rgb(255, 255, 255)">
<span style="margin:0px;font-size:large">[<a href="https://orecchia.net/event/theory-lunch/" target="_blank" rel="noopener noreferrer" data-auth="NotApplicable" data-linkindex="1" style="margin:0px" title="https://orecchia.net/event/theory-lunch/"><span data-markjs="true" class="markyk2ycimeh" data-ogac="" data-ogab="" data-ogsc="" data-ogsb="" style="margin:0px">Theory</span><span> </span><span data-markjs="true" class="mark5lphdspqc" data-ogac="" data-ogab="" data-ogsc="" data-ogsb="" style="margin:0px">Lunch</span><span> </span>Webpage</a>]<br>
[<a href="https://calendar.google.com/calendar/u/0/embed?src=c_osgf1c1qemdras8mu7l7pdhjrs@group.calendar.google.com&ctz=America/Chicago" title="https://calendar.google.com/calendar/u/0/embed?src=c_osgf1c1qemdras8mu7l7pdhjrs@group.calendar.google.com&ctz=America/Chicago"><span data-markjs="true" class="markyk2ycimeh" data-ogac="" data-ogab="" data-ogsc="" data-ogsb="" style="margin: 0px;">Theory</span><span style="margin: 0px;"> </span><span data-markjs="true" class="mark5lphdspqc" data-ogac="" data-ogab="" data-ogsc="" data-ogsb="" style="margin: 0px;">Lunch</span><span style="margin: 0px;"> </span>Calendar</a>]</span></div>
<br>
</div>
</body>
</html>