<div dir="ltr"><div class="gmail_quote"><div dir="ltr"><p dir="ltr" style="font-size:12.8px">BINGHAMTON GEOMETRY/TOPOLOGY SEMINAR</p><p dir="ltr" style="font-size:12.8px">   Date: Monday, November 9th, 2015</p><p dir="ltr" style="font-size:12.8px">   Time:  3.30 pm</p><p dir="ltr" style="font-size:12.8px">   Place: Whitney Hall, Room 100E,  followed by coffee/tea in the<br>      Hilton Reading Room. Note the new location of the math department (<a href="http://www2.math.binghamton.edu/p/directions" target="_blank">http://</a><a href="http://www2.math.binghamton.edu/p/directions" target="_blank">www2.</a><a href="http://www2.math.binghamton.edu/p/directions" target="_blank">math.binghamton.edu</a><a href="http://www2.math.binghamton.edu/p/directions" target="_blank">/p/directions</a>).</p><p dir="ltr"><span style="font-size:12.8px"> </span>  Speaker: <strong style="color:rgb(51,51,51);font-family:Arial,sans-serif;line-height:16.8px">Renato G. Bettiol</strong><span style="color:rgb(51,51,51);font-family:Arial,sans-serif;line-height:16.8px"> (University of Pennsylvania) </span></p><p dir="ltr"><font color="#333333">   Title: </font> <strong style="color:rgb(51,51,51);font-family:Arial,sans-serif;line-height:16.8px">Positive biorthogonal curvature in dimension 4</strong></p><p dir="ltr">    Abstract: <span style="color:rgb(51,51,51);font-family:Arial,sans-serif;line-height:16.8px;background-color:rgb(238,238,238)">A 4-manifold is said to have positive biorthogonal curvature if the average of sectional curvatures of any pair of orthogonal planes is positive. In this talk, I will describe a construction of metrics with positive biorthogonal curvature on the product of spheres, and then combine it with recent surgery stability results of Hoelzel to classify (up to homeomorphism) the closed simply-connected 4-manifolds that admit a metric with positive biorthogonal curvature.</span></p><p dir="ltr" style="font-size:12.8px">NOTE:  The seminar has a webpage where the semester's program is listed:</p><p dir="ltr" style="font-size:12.8px"><a href="http://www2.math.binghamton.edu/p/seminars/topsem" target="_blank">http://www2.math.binghamton.edu/p/seminars/<span>topsem</span></a></p></div>
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