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<div align="center"><big><b><big>Welcome to the 2025
Fall talks of ODTÜ-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">ODTÜ-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=20251107T1540&p1=19&ah=1"
target="_blank">Please check your time difference
between Ankara and your city here</a><br>
<b>=================================================================<br>
<br>
</b></div>
<div align="center">
<div align="center"><img
src="cid:part1.JFg7egGT.taGEzswR@bilkent.edu.tr"
alt="" width="685" height="458"></div>
</div>
<div align="center"><br>
</div>
<div align="center"><i>Jean-Leon Gerome (1824-1904)<br>
</i></div>
<div align="center"><i><br>
</i></div>
<div align="center"><i><br>
</i>
<div align="left">
<div align="left"><b><b><font color="#ff0000">Speaker:
</font> <a
href="https://akademik.baskent.edu.tr/karakas">Halil İbrahim Karakaş</a></b></b></div>
<b><b><font color="#ff0000"><font color="#000000"> </font></font></b></b><b><b><font
color="#ff0000">Affiliation: </font><i>Başkent <br>
<br>
</i></b></b></div>
<div align="left"><b><b><font color="#ff0000"> Title:
</font></b><b><font color="#ff0000"><font
color="#000000">On the enumeration of Arf
numerical semigroups with given multiplicity
and conductor<br>
<br>
</font></font></b></b></div>
</div>
<div align="justify"><b><b><font color="#ff0000">Abstract: </font></b></b>The
number of numerical semigroups with given Frobenious
number (or conductor, or genus) is one of the topics
that is studied by many researchers. In our previous
works, we have given parametrizations of Arf numerical
semigroups of small multiplicity and obtained formulas
for the number of Arf numerical semigroups with
multiplicity less than 14 and arbitrary conductor. I
presented part of these results in ODTÜ-Bikent AG
seminars 6 years ago. We noticed that the number of
Arf numerical semigroups with multiplicity m and
conductor c is (eventually) constant for some m
(especially for prime m) when restricted to some
congruence classes of c modulo m. In a recent work
with N. Tutaş, we have characterized those
multiplicities m and congruence classes of c modulo m
for which the above property holds. This talk will be
based on [<a
href="https://link.springer.com/article/10.1007/s00233-025-10503-8">Karakaş
H İ and Tutaş N, (2025), On the enumeration of Arf
numerical semigroups with given multiplicity and
conductor, Semigroup Forum 110, 308-316.</a>] where
the above characterization is given.</div>
<div align="justify"><br>
</div>
<div align="left"><font color="#ff0000"><font
color="#000000"><b><font color="#ff0000">Date:<font
color="#000000"> 7 November 2025, Friday</font></font></b></font></font></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><i><b>Participants who have registered will receive
the Zoom link via email one day before the
seminar.</b></i></p>
<p><i><b>If you registered for a previous talk in this
series, there's no need to register again—you'll
automatically receive the link for this session.</b></i></p>
<p><i><b href="mailto:sertoz@bilkent.edu.tr">If you
haven't registered yet, please contact <a
href="mailto:sertoz@bilkent.edu.tr"
class="moz-txt-link-freetext">sertoz@bilkent.edu.tr</a>
to be added to the mailing list.</b></i></p>
</blockquote>
<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"><br>
</div>
<div align="center">
<div align="center"><b><font color="#0080c0"><i><b><font
color="#0080c0"><i>This seminar series is
organized by a joint team from ODTÜ and
Bilkent<br>
<br>
Alexander Degtyarev (Bilkent)<br>
Ali Sinan Sertöz (Bilkent) contact
person<br>
Ali Ulaş Özgür Kişisel (ODTÜ)<br>
Yıldıray Ozan (ODTÜ)<br>
</i></font></b></i></font></b></div>
<br>
</div>
<br>
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<pre cols="72">----------------------------------------------------------------------------
Ali Sinan Sertöz
Bilkent University, Department of Mathematics, 06800 Ankara, Türkiye
Office: (90)-(312) - 290 1490
Department: (90)-(312) - 266 4377
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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