<div dir="ltr"><font face="arial, helvetica, sans-serif" style="font-size:13px">  BINGHAMTON GEOMETRY/TOPOLOGY SEMINAR<br><br><br>   Date: Thursday, September 17th, 2015<br><br>   Time:  2.50 pm<br><br>   Place: Whitney Hall, Room 100E,  followed by coffee/tea in the<br>      Hilton Reading Room. Note the new location of the math department (</font><a href="http://www2.math.binghamton.edu/p/directions" target="_blank" style="font-size:12.8px">http://www2.math.binghamton.edu/p/directions</a><span style="font-size:12.8px">)</span><font face="arial, helvetica, sans-serif" style="font-size:13px">.<br><br><br> </font><font face="arial, helvetica, sans-serif" style="font-size:12.7273px">  </font><font face="arial, helvetica, sans-serif" style="font-size:12.8px">Speaker: </font><span style="color:rgb(51,51,51);font-family:Arial,sans-serif;line-height:16.8px">Dmytro Yeroshkin</span><span style="color:rgb(51,51,51);font-family:Arial,sans-serif;line-height:16.8px"> (Syracuse </span><span style="color:rgb(51,51,51);font-family:Arial,sans-serif;line-height:16.8px"> University) </span><div><font color="#333333" face="Arial, sans-serif" style="font-size:12.8px"><span style="font-size:15px;line-height:16.8px"><br></span></font><div><div><font face="arial, helvetica, sans-serif" style="font-size:12.8px"><font color="#333333"><span style="line-height:21px">   Title: </span></font></font><span style="font-size:15px;color:rgb(51,51,51);font-family:Arial,sans-serif;line-height:21px"> </span><span style="color:rgb(51,51,51);font-family:Arial,sans-serif;line-height:16.8px">On Poincaré Duality for Orbifolds</span></div><div style="font-size:12.8px"><span style="font-size:12.8px;color:rgb(0,0,0)"><br></span></div><div><span style="font-size:12.8px;color:rgb(51,51,51);font-family:Arial,sans-serif;line-height:21px">    Abstract: </span><span style="color:rgb(51,51,51);font-family:Arial,sans-serif;line-height:16.8px;background-color:rgb(238,238,238)">This talk will examine the obstructions to integer-valued Poincaré duality for (underlying spaces of) orbifolds. In particular, it will be shown that in dimensions 4 and 5, the obstruction is controlled by the orbifold fundamental group. A consequence of this is that if the orbifold fundamental group is naturally isomorphic to the fundamental group of the underlying space, then the orbifold satisfies integer-valued Poincaré duality.</span></div></div><div style="font-size:12.8px"><span style="color:rgb(51,51,51);font-family:Arial,sans-serif;font-size:15px;line-height:16.8px"><br></span></div><div style="font-size:12.8px"><span style="font-family:arial,helvetica,sans-serif;font-size:12.8px">NOTE:  The seminar has a webpage where the semester's program is listed:</span><br style="font-family:arial,helvetica,sans-serif;font-size:12.8px"><br style="font-family:arial,helvetica,sans-serif;font-size:12.8px"><a href="http://www2.math.binghamton.edu/p/seminars/topsem" target="_blank" style="font-family:arial,helvetica,sans-serif;font-size:13px">http://www2.math.binghamton.<u></u>edu/p/seminars/<span class="">topsem</span></a></div></div></div>