Algebraic Graph Theory International Webinar (4.10.2022)

v utorok 4.10.2022 o 19:00 hod.

03. 10. 2022 21.18 hod.
Od: Róbert Jajcay

The organizers of the Algebraic Graph Theory International Webinar would like to invite you to join us and other colleagues on October 4, 2022, at 7pm Central European Summer Time (= 5pm UTC), for the next presentation delivered by Vladislav Taranchuk. 

The title of Martin's talk: On the eigenvalues of the graphs D(5,q)

Let q = p^e, where p is a prime and e is a positive integer. The family of graphs D(k, q), defined for any positive integer k and prime power q, were introduced by Lazebnik and Ustimenko in 1995. To this day, the connected components of the graphs D(k, q), provide the best known general lower bound for the size of a graph of given order and given girth. Furthermore, Ustimenko conjectured that the second largest eigenvalue of D(k, q) is always less than or equal to 2sqrt{q}. In this talk, we will discuss some of the recent progress on this conjecture, including new results that show that the second largest eigenvalue of D(5, q) is less than or equal to 2sqrt{q} when q is an odd prime power. This result is obtained through the use of representation theory and so a portion of the talk will be dedicated to giving a background on the tools used to prove the result.
This is joint work with Himanshu Gupta.


The Zoom link for this semester is:
Meeting ID: 871 9332 0713
Passcode: 653250

Further details may be found at

where you can also find the slides and the recordings of our previous presentations. Also, if you wish to advertise an AGT friendly conference on this page, please send us the link.  

Hoping to see you at the webinar, and wishing you all the best. 

Isabel HubardRobert Jajcay and Primoz Potocnik