Events

LabAGTA Seminar: Michael Tsatsomeros (Washington State University, Pullman),
November 3, 2023, 13:4514:45.
Title: Rank one perturbations for cone reachability and holdability.
Abstract: A choice of feedback control in a linear control system is proposed in order for the
trajectory to eventually enter the nonnegative orthant and remain therein for all time thereafter.
This is achieved by imposing the strong PerronFrobenius property and involves altering the
eigenvalues, as well as the left eigenvectors via rank one perturbations.

LabAGTA Seminar: Mihir Kumar Chakraborty (Jadavpur University, Kolkata),
May 12, 2023, 15:3016:30.
Title: Some aspects of mathematical pluralism.
Abstract: In this talk, I will provide examples of plurality in mathematics caused because of both
the internal as well as external reasons. Thus it will be argued that culture, being understood in a wider sense,
plays a significant role in the creation and development of mathematical notions. Recent research called
``Mathematical practices'' and ``Proof events'' may also have justification from this perspective of multiplicity.
As a result, from the angles of content and method current uniformity all over the world needs a critical review.

LabAGTA Seminar: Christian Kassel (CNRS and Universite de Strasbourg),
March 21, 2023, 15:0016:30.
Title: On combinatorial zeta functions.
Abstract: A generating function is a way of encoding an infinite sequence of numbers
by a formal power series. There are various types of such functions.
In my talk I will concentrate on one of them called zeta functions and exhibit several examples of interest.
In some emblematic cases which I will describe such zeta functions are rational functions.
Finally I will present an idea of Kontsevich which leads to a class of zeta functions which are algebraic functions.

Logic and Formal Methods, UNILOG ATHENS 2022, September 22, 2022.
Morning session (on line, https://centralntua.webex.com/meet/pstef), 09:3012:30.
Razvan Diaconescu (invited).
Maria Dimarokgona,
Asterios Gatzounis,
Theodoros Mitsikas,
Giorgos Pitsiladis,
Dimitris Zafirakopoulos,
Foivos Skarpelos,
Iakovos Ouranos,
Dimitra Serakioti,
Kostas Barlas.
Afternoon session (Teleteaching Room, Library N.T.U.A., Multimedia Center), 14:0018:00.
Jean Yves Beziau (invited).
Ioannis Kiouvrekis,
Katerina Ksystra  Nikos Triantafyllou,
Sofia Almpani,
Manthos Bournazos,
Ioannis Vandoulakis.
Round table discussion.

LabAGTA Seminar: Khaled Bataineh (Jordan University of Science and Technology),
April 14, 2022, 11:3012:30.
Title: New polynomial invariants of knotoids and the theory of polar knots.
Abstract: We introduce new polynomial invariants for both planar knotoids
and spherical knotoids. To introduce these invariants, we first introduce what
we call polar knots, and give the fundamentals of their theory.

LabAGTA Seminar: Paolo Cavicchioli (University of Modena), March 31, 2022, 11:3012:30.
Title: An algorithmic method to compute platlike Markov moves for genus two 3manifolds.
Abstract: The talk deals with equivalence of links in 3manifolds of Heegaard genus 2. Starting from a description
of such a manifold introduced in [1], that uses 6tuples of integers and determines a Heegaard decomposition of the
manifold, we construct an algorithm (implemented in c++) which allows to find the words in B_{2, 2n}, the braid group
on 2n strands of a surface of genus 2, that realizes the platequivalence for links in that manifold.
In this way, we extend to the case of genus 2 the result obtained in [2] for genus 1 manifolds.
We describe in particular a case of this construction.
[1] Casali, M. R. & Grasselli, L. 2symmetric crystallizations and 2fold branched coverings of S3. Discrete Math. 87, 922 (1991).
[2] Cattabriga, A. & Gabrovsek, B. A Markov theorem for generalized plat decomposition. Ann. Sc. Norm. Super. Pisa Cl. Sci. XX, 12731294 (2018).

LabAGTA Seminar: Paolo Cavicchioli (University of Modena), March 24, 2022, 11:3012:30.
Title: Plat closure of braids in E^3.
Abstract: In this seminar, we will define what a plat closure of braid is, describe its main properties
and its relation to Hilden groups. In the second part of the seminar we will answer to the problem of passing
from the plat form of a braid to the standard one and vice versa.