[Turkmath:7307] ODTU-Bilkent Algebraic Geometry Seminar-Zoom-570

[Ali Sinan Sertöz]

*Welcome to the 2025 Fall talks of ODTÜ-Bilkent Algebraic Geometry 
Seminars**
*
/since 2000/
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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=20251024T1540&p1=19&ah=1>
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*

/Jean-Leon Gerome (1824-1904)
/
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**Speaker: Türkü Özlüm Çelik <https://sites.google.com/view/tocj/home>**
******Affiliation://**/*Max Planck*/
**/
/**
**Title: Interaction Networks via Grassmannians
**
**
**Abstract: **When can a network of mutually reinforcing N components 
remain stable? To approach such questions, we describe the interactions 
through generalized Lotka–Volterra equations—a broad class of dynamical 
systems modeling how components influence one another over time. This 
formulation leads to a family of semi-algebraic sets determined by the 
sign pattern of the parameters. These sets encode positivity conditions 
defining regions of potential coexistence, with polynomial degrees 
growing exponentially in N. Embedding the parameter space into the real 
Grassmannian Gr(N,2N) transforms these conditions into sign relations 
governed by the Grassmann–Plücker equations and oriented matroids. This 
geometric reformulation yields a realization problem through which we 
detect impossible interaction networks and study the algebraic structure 
underlying stability. If time permits, we will also touch on how these 
structures connect to algebraic curves. This talk is based on our recent 
work arXiv:2509.00165 <https://arxiv.org/abs/2509.00165>.****

*Date: 24 October 2025, 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)
/*/*

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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> 
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