[Turkmath:7464] ODTU-Bilkent Algebraic Geometry Seminar-Zoom-585

[Ali Sinan Sertöz]

*Welcome to the 2026 Spring talks of ODTÜ-Bilkent Algebraic Geometry 
Seminars**
*
/since 2000/
**=================================================================**

This week the ODTÜ-Bilkent Algebraic Geometry Seminar 
<http://www.bilkent.edu.tr/~sertoz/agseminar.htm>  is *online*

/This talk will begin at _*15:40*__ (GMT+3)_/
Please check your time difference between Ankara and your city here 
<https://www.timeanddate.com/worldclock/fixedtime.html?msg=ODT%C3%9C-Bilkent+Algebraic+Geometry+Seminar&iso=20260417T1540&p1=19&ah=1>
*=================================================================

*

/Ben Viegers (1886-1947)
/
/
/
/
/
**Speaker: Alexander Degtyarev <http://www.fen.bilkent.edu.tr/%7Edegt/>**
******Affiliation: /Bilkent

/**
**Title:  A decade of line counting: an overview

**
**Abstract:**  I will give a brief overview of a long project that 
started a decade ago (in collaboration with Ilia Itenberg and Sinan 
Sert\"oz and in parallel with S{\l}awomir Rams and Matthias Sch\"utt) 
and originally intended to bridge a minor gap in the proof of Segre's 
celebrated theorem on 64 lines on a smooth quartic surface. Confining 
ourselves to polarized K3-surfaces, now we manage to answer questions 
that no one even dared to ask, mostly because of lack of tools. For 
example, we

  * obtained sharp upper bounds on the possible number of lines on a
    smooth polarized $K3$-surface of any degree,

  * obtained similar bounds for quartics, sextics, and octics with
    singularities,

  * advanced in the understanding of conics on $K3$-surfaces,

  * started the study of twisted cubics.

I will try to discuss both classical (more than 5 years old) results and 
recent advances; if time permits, I will also try to outline the
techniques used.
*
*
*Date: 17 April 2026, Friday*
*Time: 15:40 /(GMT+3)/*
*Place: **Zoom*

    /*Participants who have registered will receive the Zoom link via
    email one day before the seminar.*/

    /*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.*/

    /*If you haven't registered yet, please contact
    sertoz at bilkent.edu.tr to be added to the mailing list.*/

You are most cordially invited to attend.

Ali Sinan Sertöz

*/*/This seminar series is organized by a joint team from ODTÜ and Bilkent

Alexander Degtyarev (Bilkent)
Ali Sinan Sertöz (Bilkent) contact person
Ali Ulaş Özgür Kişisel (ODTÜ)
Yıldıray Ozan (ODTÜ)
/*/*


------------------------------------------------------------------------

----------------------------------------------------------------------------
Ali Sinan Sertöz
Bilkent University, Department of Mathematics, 06800 Ankara, Türkiye
Office: (90)-(312) - 290 1490
Department: (90)-(312) - 266 4377
e-mail:sertoz at bilkent.edu.tr <mailto:sertoz at bilkent.edu.tr> 
Web:sertoz.bilkent.edu.tr <http://sertoz.bilkent.edu.tr> 
----------------------------------------------------------------------------
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://yunus.listweb.bilkent.edu.tr/pipermail/turkmath/attachments/20260413/86936bba/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: CVhASc37dt0DtZp8.jpg
Type: image/jpeg
Size: 874792 bytes
Desc: not available
URL: <http://yunus.listweb.bilkent.edu.tr/pipermail/turkmath/attachments/20260413/86936bba/attachment-0001.jpg>