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<div align="center"><big><b><big>Welcome to the 2023
Spring talks of ODTU-Bilkent Algebraic
Geometry Seminars</big></b></big><b><br>
</b></div>
<div align="center"><i>since 2000</i><br>
</div>
<div align="center"><b><b>=================================================================</b></b><br>
<br>
This week the <a
href="http://www.bilkent.edu.tr/~sertoz/agseminar.htm"
target="_blank">ODTU-Bilkent Algebraic Geometry
Seminar</a> is <b>online</b><br>
<br>
<i><font color="#ff00ff">This talk will begin at <u><b>15:40</b></u><u> (GMT+3)</u></font></i><br>
<a
href="https://www.timeanddate.com/worldclock/fixedtime.html?msg=ODT%C3%9C-Bilkent+Algebraic+Geometry+Seminar&iso=20230331T1540&p1=19"
target="_blank">Please check your time
difference between Ankara and your city here</a><br>
<b>=================================================================</b></div>
<div align="center">
<div align="center"><img
src="cid:part1.iXPiSs0L.31CcVCIU@bilkent.edu.tr"
alt="image.png" width="415" height="562"></div>
<div align="center"><b> </b><br>
</div>
<font size="2"><i>Edouard Leon Cortes (1882-1969)<br>
</i></font></div>
<div align="center"><br>
<div align="left"><b><b><font color="#ff0000">Speaker:<font
color="#000000"> <a
href="https://avesis.metu.edu.tr/tkarayay">Tolga
Karayayla</a><br>
</font></font></b></b><b><b><font
color="#ff0000">Affiliation: </font><i>ODTÜ</i></b></b><b><b><font
color="#ff0000"><br>
Title:<font color="#000000"> On a class of
non-simply connected Calabi-Yau 3-folds
with positive Euler characteristic-Part
1<br>
</font><br>
</font></b></b></div>
</div>
<div align="left"><b><b><font color="#ff0000">Abstract:</font></b></b><font
color="#ff0000"><font color="#000000"> </font></font><br>
<div align="justify"><font color="#ff0000"><font
color="#000000">In this talk I will present
a class of non-simply connected Calabi-Yau
3-folds with positive Euler characteristic
which are the quotient spaces of
fixed-point-free group actions on
desingularizations of singular Schoen
3-folds. A Schoen 3-fold is the fiber
product of two rational elliptic surfaces
with section. Smooth Schoen 3-folds are
simply connected CY 3-folds.
Desingularizations of certain singular
Schoen 3-folds by small resolutions have the
same property. If a finite group G acts
freely on such a 3-fold, the quotient is
again a CY 3-fold. I will present how to
classify such group actions using the
automorphism groups of rational elliptic
surfaces with section. The smooth Schoen
3-fold case gives 0 Euler characteristic
whereas the singular case results in
positive Euler characteristic for the
quotient CY threefolds.<br>
</font></font></div>
</div>
<div align="left"><font color="#ff0000"><font
color="#000000"> <br>
</font></font></div>
<div align="left"><font color="#ff0000"><font
color="#000000"><b><font color="#ff0000">Date:<font
color="#000000"> 31 March 2023</font></font></b>,
<b>Friday</b></font></font><br>
</div>
<div align="left"><font color="#ff0000"><font
color="#000000"><b><font color="#ff0000">Time: </font>15:40 <i>(GMT+3)</i></b><br>
<b><font color="#ff0000">Place: </font></b><font
color="#ff0000"><font color="#000000"><b>Zoom</b></font></font></font></font></div>
<blockquote>
<p><font color="#ff0000"><font color="#000000"><font
color="#ff0000"><font color="#000000"><b><b
style="color:rgb(51,51,51);font-family:arial,verdana,sans-serif;font-size:14px">One
day before the seminar, an
announcement with the Zoom meeting
link will be sent to those who
registered with Sertöz.<br>
</b></b></font></font></font></font></p>
<p><font color="#ff0000"><font color="#000000"><font
color="#ff0000"><font color="#000000"><b><b
style="color:rgb(51,51,51);font-family:arial,verdana,sans-serif;font-size:14px">If
you have registered before for one
of the previous talks, there is no
need to register again; you will
automatically receive a link for
this talk too.<br>
</b></b></font></font></font></font></p>
<p><font color="#ff0000"><font color="#000000"><font
color="#ff0000"><font color="#000000"><b><b
style="color:rgb(51,51,51);font-family:arial,verdana,sans-serif;font-size:14px">If
you have not registered before,
please contact him at <a
href="mailto:sertoz@bilkent.edu.tr?subject=Zoom%20Seminar%20Address%20Request"
target="_blank">sertoz@bilkent.edu.tr</a>.</b></b></font></font></font></font></p>
</blockquote>
<div align="left"><br>
</div>
<div align="left">You are most cordially invited to
attend.</div>
<div align="left"><br>
</div>
<div align="left">Ali Sinan Sertöz</div>
<div align="left"><font size="1"><i>(PS: To
unsubscribe from this list please send me a
note.)</i></font> </div>
<hr>
<pre cols="72">----------------------------------------------------------------------------
Ali Sinan Sertöz
Bilkent University, Department of Mathematics, 06800 Ankara, Türkiye
Office: (90)-(312) - 290 1490
Department: (90)-(312) - 266 4377
Fax: (90)-(312) - 290 1797
e-mail: <a href="mailto:sertoz@bilkent.edu.tr" target="_blank" class="gmail-moz-txt-link-freetext moz-txt-link-freetext">sertoz@bilkent.edu.tr</a>
Web: <a href="http://sertoz.bilkent.edu.tr" target="_blank">sertoz.bilkent.edu.tr</a>
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---------------------------------------------------------------------------- <br>
Ali Sinan Sertöz <br>
Bilkent Üniversitesi, Matematik Bölümü, 06800 Ankara <br>
Ofis Tel: (312) - 290 1490 <br>
Bölüm Sekreterliği: (312) - 266 4377 <br>
Fax: (312) - 290 1797 <br>
e-posta: <a href="mailto:sertoz@bilkent.edu.tr"
class="moz-txt-link-freetext"> sertoz@bilkent.edu.tr</a> <br>
Anasayfa: <a href="http://sertoz.bilkent.edu.tr/">sertoz.bilkent.edu.tr</a><br>
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