Seminár z algebraickej teórie grafov - Štefan Gyürki (1.4.2022)

v piatok 1.4.2022 o 13:00 hod. v miestnosti M/X aj online formou

30. 03. 2022 17.17 hod.
Od: Martin Mačaj

Prednášajúci: Štefan Gyürki (Slovenská technická univerzita)

Názov: Bipartite biregular cages from the construction of bi-coset graphs

Termín: 1.4.2022, 13:00 hod., M X a MS Teams (AGT in Bratislava team, scheduled meeting)

Abstrakt:
A bi-coset graph $\Gamma_{(G;H,K)} $ is a bipartite graph with the two vertex sets consisting of the cosets of subgroups $H, K$ of a group $G$, and the adjacency determined by non-empty intersection. Bi-coset graphs constitute a classical object of algebraic graph theory and have been studied in various contexts.
In this talk, bi-coset graphs are used in connection with the problem of finding a smallest biregular graph of girth $g$ with the vertices of degrees $m,n$.
A few bipartite biregular bi-coset cages will be presented, as well as an infinite family of small bipartite biregular graphs will be constructed.
This work is joint with: R. Jajcay, P. Jánoš, J. Širáň, Y. Wang

Thanks to (temporary?) loosening of restrictions regarding the COVID epidemy, we intend to conduct the seminar meetings this semester `in-person'. Hence, all of you who might choose to attend in person are welcome. Those of you who are not able to attend in person or who are still uncertain about the safety of attending in person are welcome to attend via MS Teams. In either case, we hope to see as many of you as possible (either in person or virtually) at our Friday gatherings.