An online session of the Algebra and Logic Seminar will be held on November 5, 2021 (Friday) at 1:00 p.m. (UTC +2).

A talk on

Permutation groups and permutation patterns

will be delivered by Erkko Lehtonen (Universidade Nova de Lisboa, Portugal).

Abstract. 

We approach permutations from two different points of view: the algebraic one of permutation groups and the combinatorial one of permutation patterns. While these two well-established notions do not seem to have much in common, there is a perhaps surprising connection that will be explained in this talk. Namely, the class of permutations avoiding the complement of a permutation group is comprised of levels that are permutation groups. With the help of invariant relations, we describe the permutation groups that arise in this way from pattern avoidance. Furthermore, we propose refinements to the work by Atkinson and Beals on permutation classes in which all levels are groups.

This talk is partly based on joint work with Reinhard Pöschel (Technische Universität Dresden).

The seminar will be held via Zoom and everyone can join at:

https://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 

Topic: Онлайн семинар на секция “Алгебра и логика”
Time: Nov 05, 2021 01:00 PM Sofia
Meeting ID: 851 3737 5021
Passcode: 035647

Algebra and Logic Department, IMI-BAS
http://www.math.bas.bg/algebra/seminarAiL/
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