Archief

Datum: 13/3/2020 Tijd: 14:30	Integration on supermanifolds In this talk I will give an introduction to integration on supermanifolds. I will start with an overview of the different approaches on integration used in the non-super setting. Then following the article "Integration on non-compact supermanifolds" by Alldridge, Hilgert and Palzer, I will introduce the integral on supermanifolds using Berezin densities and forms. I will discuss some pathologies of this integral and possible solutions. In the examples I will focus on the supersphere and on the superhyperboloid used in my construction of the minimal representation of the orthosymplectic supergroup.
Plaats: s8, 3.1
Organisator: Sigiswald Barbier

Datum: 9/3/2020 Tijd: 19:00	Jobavond voor wiskundigen, informatici en fysici Na het succes van vorig jaar slaat PRIME nogmaals de handen ineen met de VVN, Zeus WPI en WiNA tijdens een jobavond. Gedurende de avond komen enkele afgestudeerden vertellen over hun beroep, hoe zij daar zijn terechtgekomen en hoe zij juist hun opgenomen kennis uit de studentenjaren in de praktijk gebruiken. Ga jij het komende jaar op zoek naar een job en wil je eens horen welke kanten je kan uitgaan? Is de jobkeuze nog veraf maar wil je gewoon eens voorproefje van je toekomstige mogelijkheden krijgen? In elk geval ben je welkom op deze jobavond. Er zullen een 10-tal enthousiaste alumni uit uiteenlopende branches aanwezig zijn die ieder een 5-tal minuten praten. Na deze reeks voorstellingen is er ruimte voor informele gesprekken met de afgestudeerden, waarin je contacten kan leggen en al je vragen kan stellen. We danken de Opleidingscommisie Wiskunde, Fysica & sterrenkunde en Informatica voor hun bijdrage aan deze avond. 19:00: Deuren open. 19:30: Start presentaties. 20:30: Netwerken met de afgestudeerden met een drankje en hapje.
Plaats: S9, auditorium A3
Organisator: PRIME, VVN, Zeus WPI en WiNA

Datum: 28/2/2020 Tijd: 14:30	Fock model and Segal-Bargmann transform for the orthosymplectic Lie superalgebra The classical Segal-Bargmann is an integral transform between the Schrödinger space of square-integrable functions and the Fock space of holomorphic functions. The Segal-Bargmann transform was reinterpreted by Hilgert-Kobayashi-Möllers-Ørsted as an intertwining operator between realisations on the Schrödinger and the Fock space of the minimal representation of a Lie group. In this talk I will give a generalisation of this approach to superspaces in order to obtain a Segal-Bargmann transform as an integral transform that intertwines the Schrödinger and Fock model for the orthosymplectic Lie superalgebra osp(m,2|2n).
Plaats: s8, les 3.1
Organisator: Sam Claerebout

Datum: 29/1/2020 Tijd: 11:00	Talk by Liviu IXaru It is my pleasure to invite you to the lecture by Prof. dr. Liviu Ixaru (Horia Hulubei National Institute of Physics and Nuclear Engineering , Bucarest) , entitled “Runge-Kutta methods of special type”. The lecture will be held on Wednesday January 29, at 11h00 in lecture room 1.1, building S9. The abstract is enclosed below. With best regards, Marnix Van Daele ------------------------------------------------------ "Runge-Kutta methods of special type" Abstract The coefficients of the traditional forms of the Runge-Kutta methods are constant but a series of proposals have appeared along time for equation dependent coefficients adapted in terms of various criteria. We choose the stability properties for such a criterion. This is because methods with high stability properties are required for differential equations with fast decaying solutions, and many phenomena of sustained interest nowadays (decay, absorption, dissociation etc.) are of this type. We show that, after such a treatment, even explicit versions of the Runge-Kutta method, known as very weak for stability in their standard form, become A-stable. As an application we present results for a hot problem in biophysics, in the area of efforts of producing pharmaceutical drugs with gradual release of the active substance.
Plaats: S9, leszaal 1.1
Organisator: Marnix Van Daele

Datum: 24/1/2020 Tijd: 14:30 - 16:00	Defining relations for quantum symmetric pair coideals of Kac-Moody type Classical symmetric pairs consist of a Kac-Moody algebra g together with its subalgebra of fixed points under an involutive automorphism. Quantum analogs of this construction, known as quantum symmetric pairs, replace the fixed point Lie subalgebras of g by one-sided coideal subalgebras of the quantum group U_q(g). In this talk I will explain this construction and give some motivation and examples arising from quantum integrability. Special attention will be drawn to the presentation of these algebras by generators and relations. I will present a novel set of defining relations of q-Serre or q-Dolan-Grady type for these quantum symmetric pair coideals, based on two different methods. One uses a projection technique established by Letzter and Kolb, the other builds on q-binomial identities.
Plaats: s8, les 3.1
Organisator: Hadewijch De Clercq

Datum: 29/11/2019 Tijd: 13:00	Min-max theorem for a spanning tree with constraints on the leaf degree Shunichi Maezawa Yokohama National University, Yokohama, Japan Abstract: The leaf degree of a vertex x in a tree is defined as the number of end-vertices in the tree adjacent to x. In 2001, Kaneko gave a necessary and sufficient condition for a graph to have a spanning tree with bounded maximum leaf degree. We generalize Kaneko's result. Moreover, we give the maximum order of a tree with constraints on the leaf degree in a graph. It is called a min-max theorem or Berge-Tutte type theorem.
Plaats: S9, leszaal 1.1
Organisator: Carol Zamfirescu

Datum: 20/11/2019 Tijd: 13:30 - 14:15	Lezing: Horizon-unbiased Investment with Ambiguity Speaker: Dr. Xianming Sun Abstract: In the presence of ambiguity about the driving force of market randomness, we consider the dynamic portfolio choice problem without any predetermined investment horizon. The investment criterion is formulated as a robust forward performance process, reflecting an investor's dynamic preference adapted to the market evolution. We show that the market risk premium and the utility risk premium jointly determine the investors' trading direction and the worst-case scenarios of the risky asset's mean return and volatility. The closed-form formulas for the optimal investment strategies are given in the special settings of the constant relative risk aversion(CRRA) preference. The resulting portfolio strategies highlight the effect of ambiguity on nonparticipation in the risky asset market from the forward performance point of view.
Plaats: leslokaal 3.2, S9
Organisator: Prof. M. Vanmaele

Datum: 13/11/2019 Tijd: 10:00	Logic & Analysis seminar Speaker: Frederik Broucke Title: Well-behaved Beurling primes and integers. Abstract: A Beurling generalized prime system is a non-decreasing sequence of real numbers greater than 1 tending to infinity. These numbers are called the generalized primes. The corresponding Beurling generalized integers are the numbers you obtain by considering all possible products of these primes, and the number 1. With these sequences, one associates the counting functions pi(x) and N(x), which count the number of primes (integers) below x. These generalized number systems were introduced by Beurling to study the minimal conditions on N required to obtain the Prime Number Theorem. In this talk, we will discuss well-behaved primes and integers. The primes resp. integers are well-behaved if the respective counting function has a certain prescribed asymptotic behavior with error term O(x^a) for some a<1. We will discuss the implications for the primes of having well-behaved integers, and vice-versa. We will also discuss the optimality of these result. This talk is based on collaborative work with Gregory Debruyne and Jasson Vindas.
Plaats: Building S8, vergaderzaal 3.2
Organisator: Andreas Debrouwere

Datum: 12/11/2019 Tijd: 19:00	Lezing: Schering en inslag Op dinsdag 12 november (19:00, S9, A3) organiseert PRIME een voordracht over de link tussen priemgetallen, kettingbreuken en weefgetouwen. De sprekers zijn Paul Levrie en Rudi Penne, auteurs van het boek "De pracht van de priemgetallen". De kerststelling van Fermat zegt dat een oneven Prime p te schrijven is al de som van twee kwadraten Desda p van de vorm 4n+1 is. Dit heeft bijvoorbeeld gevolgen bij het weven van satijn, waar een Prime van deze vorm leidt tot een zeer symmetrisch (en dus erg mooi) patroon. Met behulp van die weefpatronen kunnen we op een elegante manier grafisch aan getaltheorie doen. Zo vinden we een verband met kettingbreuken, waar de meest symmetrische vorm, een palindromische kettingbreuk, blijkt overeen te komen met het meest symmetrische weefpatroon. We laten onderweg geen kans voorbijgaan om ons en jullie te ontspannen met de kerstsokstelling en andere wiskundige weetjes die wellicht met andere feesten kunnen geassocieerd worden.
Plaats: S9, auditorium A3
Organisator: PRIME

Datum: 6/11/2019 Tijd: 10:00	Logic & Analysis seminar Speaker: Jasson `Vindas Title: On integers with number of prime factors in a given residue class Abstract: Recently, Gregory Debruyne has shown that the number of integers below a given number x and having number of prime factors in a specified residue class mod K is asymptotically equal to x/K. Furthermore, the result admits generalization to other number systems satisfying low regularity assumptions. In this talk we will present a proof of this result and explain some analytic machinery behind it. In particular, we will discuss extensions of the Halasz-Wirsing mean-value theorem due to G. Debruyne, F. Maes, and myself.
Plaats: Building S8, lecture hall 0.1
Organisator: Andreas Debrouwere

Datum: 30/10/2019 Tijd: 17:30	Infosessie over Erasmus-uitwisseling Op woensdag 30 oktober 2019 zal door Prof. dr. L. Storme (verantwoordelijke internationalisering voor de wiskunde-opleiding)  een infosessie gegeven worden over Erasmus-uitwisseling. Dit zal doorgaan in leslokaal 2.4 van gebouw S8 vanaf 17u30.
Plaats: S9, leslokaal 2.4
Organisator: prof. L. Storme

Datum: 30/10/2019 Tijd: 11:30	Logic & Analysis seminar Speaker: David Fernández-Duque Title: Monadic logic and European transport regulations Joint work with Ana de Almeida Borges, Juan José Conejero Rodríguez, Mireia González Bedmar, and Joost Joosten Abstract: Trucks and similar vehicles are fitted with tachographs which record activities (driving, resting, etc.) second by second. European transport regulations place restrictions on these activities, for example prescribing minimal weekly rest periods. In order to enforce the law, it is necessary to develop software that can analyze this data and check whether it complies with the regulations. However, there is a problem in that the law is written in natural language, and hence must be formalized before it can be treated computationally. In this talk we argue that the law can be formalized within the \Sigma^1_1 fragment of monadic second order logic interpreted over the natural numbers, and explore its expressibility in monadic first order logic, in the guise of linear temporal logic. We present some results which suggest that second order quantification is necessary, an undesirable feature with respect to computational considerations.
Plaats: Building S8, lecture hall 2.2
Organisator: Andreas Debrouwere

Datum: 25/10/2019 Tijd: 11:30 - 12:30	Lunchtalk elemath Op vrijdag 25 oktober zal prof. dr. dr. Kris Coolsaet zijn project Elemath toelichten tijdens een lunchtalk (11u30- 12u30). Met Elemath, ontwikkeld aan onze faculteit, kunnen studenten hun basiswiskundecompetenties online testen en trainen. Elemath biedt automatisch gegenereerde oefeningen aan waarvan het niveau is aangepast aan de vorderingen die de student op dat specifieke onderwerp reeds heeft gemaakt. Als bijkomende extra kan u oefeningen laten aanmaken voor uw examens, meteen knip-en-plak-klaar in LaTeX. Wil u graag meer te weten komen over dit innovatief onderwijsproject? Inschrijven, graag vóór 17 oktober, via https://eventmanager.ugent.be/elemath Een broodje en drankje wordt voorzien. Kan u deze uitnodiging verder verspreiden naar geïnteresseerde assistenten en onderwijsbegeleiders? Hartelijk dank!
Plaats: S2, vergaderzaal 2.1
Organisator: Kris Coolsaet

Datum: 23/10/2019 Tijd: 10:00	Logic & Analysis seminar Speaker: Junqing Huang Title: Intrinsic image transfer for illumination manipulation. Abstract: Intrinsic image decomposition (IID) strives to factorize an image into sub-layers to characterize the illumination and intrinsic attributes. Despite its multiple applications in image processing and computer vision, it is, in general, a highly ill-posed problem. We propose an intrinsic image transfer (IIT) algorithm for illumination manipulation, which differs from the prevailing Retinex-like methods without the necessity of taking an intrinsic image decomposition. The model creates a local image translation between two illumination surfaces, which is built on a generalized optimization framework consisting of three photorealistic losses derived from image illumination, reflectance and content respectively. We illustrate that all losses can be relaxed into quadratic forms, giving a closed-form solution for image illumination manipulation. .
Plaats: Building S8, lecture hall 2.2
Organisator: Andreas Debrouwere

Datum: 16/10/2019 Tijd: 10:00	Logic & Analysis seminar Speaker: Andreas Weiermann Title: Using Büchi automata to prove limit laws for ordinals Abstract: Let phi be a formula about orderings. We will show within a natural framework: There will exist a real number r such that phi holds on a randomly chosen alpha,< with probability r. Our proof is based on results from automata theory combined with generatingfunctionology. This is joint work with Alan R. Woods. Everybody is welcome. The talk is aimed at a general audience.
Plaats: Building S4, lecture hall 0.3
Organisator: Andreas Debrouwere

Datum: 8/10/2019 Tijd: 17:30 - 19:30	Presentatie van de stages in de opleiding wiskunde In het masterprogramma wiskunde kan het vak stage gevolgd worden (hetzij als vak uit de minor onderzoek, hetzij als keuzevak). Tijdens de voorbije zomermaanden hebben zes wiskunde-studenten hun stage afgelegd. Op dinsdag 8 oktober zullen zij (vanaf 17u30 tot ongeveer 19u30) hun stagewerk presenteren. Onderaan deze e-mail vinden jullie het uurschema terug. Ze zullen het, naast de bespreking van de inhoud van de stage, ook hebben over hoe zij de stage hebben ervaren, in welke omgeving zij terechtkwamen, hoe ze werden begeleid, enz. Op de presentaties zullen ook enkele begeleiders van de stages uit de bedrijven aanwezig zijn. Graag nodig ik lesgevers en studenten uit op deze presentaties. Met vriendelijke groeten, prof. M. Van Daele verantwoordelijk lesgever voor het vak stage ------------------------------------------------------------ Presentaties van de stages in de opleiding wiskunde  dinsdag 8 oktober 2019 - auditorium A1 - gebouw S9 17u30   Cedric De Donder - Yazzoom: TCN’s en een Bayesiaanse kijk op Machine Learning 17u50    Jurriën Puype - Robovision: TCN’s en een Bayesiaanse kijk op Machine Learning 18u10    Steven Van Overberghe - Comsof: Optimale routering in netwerken met meerdere bronnen 18u30    Yucatan De Groote - KBC: Granularity adjustment with name concentration risk 18u50    Freija Verbeke  - FOD Binnenlandse Zaken : Cryptography in an ever-changing world 19u10    Dagmar Bemelmans - Cegeka: Anomalie detectie met behulp van neurale netwerken
Plaats: S9, aud A1
Organisator: Marnix Van Daele

Datum: 8/8/2019 Tijd: 15:00	Infinite regular extensions of disc triangulations Infinite regular extensions of disc triangulations Markus Baumeister Lehrstuhl B für Mathematik (Algebra), RWTH Aachen University, Germany We consider the set of all finite triangulations of a topological disc, whose inner vertices only have degrees 4, 5 and 6, and whose boundary vertices have degree at most 5. Even combinatorially, this is a huge set without any apparent structure. A possible approach to gain insight into its structure is to introduce operations that modify triangulations locally. In this talk, I work with the operation “butterfly insertion”, which inserts two triangles into a given triangulation. Then, I analyse which triangulations can be obtained from one another by applying this operation. In the main result I identify an implicit “global structure”, which is an invariant of the operation. To tease out this global structure, I define an infinite surface extending a triangulation. Then I classify the different types of infinite extensions that can appear.
Plaats: S9, leszaal 1.1
Organisator: Gunnar Brinkmann

Datum: 24/7/2019 Tijd: 15:00	In Search of Coulson’s Lost Theorem In Search of Coulson’s Lost Theorem Patrick W Fowler and Barry Pickup Department of Chemistry, University of Sheffield, UK The simplest description of conjugated hydrocarbons is Hückel Molecular Orbital (HMO) Theory, which is in essence a graph theoretical model. Eigenvectors and eigenvalues of the adjacency matrix of the molecular graph are used to model spatial distributions and energies of the mobile electrons that dominate the chemical and physical properties of these unsaturated systems. Charles Alfred Coulson FRS (1910-1974) was a leading figure in the development of HMO theory from the 1940s to the 1970s. His work defined key concepts that still shape chemical thinking about benzenoids and have found new applications with the plethora of new forms of carbon and carbon nanostructures that have emerged in the decades since his death. This talk will discuss a result that surfaced in Coulson’s early work, is part of the folklore of HMO theory, believed by all chemists, but with so far no complete published proof, despite tantalising hints sprinkled through 70 years of literature. Part of the work described in this talk was carried out in collaboration with Nino Bašić (University of Primorska) and Henry Zubaida (U Sheffield).
Plaats: S9, leszaal 1.1
Organisator: Gunnar Brinkmann

Datum: 9/7/2019 Tijd: 14:00	Talk on Computing Ramsey numbers by Brendan McKay Brendan McKay (Australian National University) who is currently staying at our university as an "International Francqui Chair" will be giving a talk on Ramsey numbers on Tuesday 9 July at 14h00 in Lecture room 3.1 of Building S9. You are of course cordially invited to attend this lecture. It is part of the "Francqui lecture series" which he will be giving at various Belgian universities (see www.ugent.be/mckay for more information). Title: Computing Ramsey numbers Abstract: The classical Ramsey number R(s,t) is the smallest n such that, for every colouring of the edges of the complete graph K_n using two colours, there is either an s-clique of the first colour or a t-clique of the second colour. Despite considerable effort by many people over decades, only a handful of classical Ramsey numbers are known exactly. The most recent determination R(4,5)=25 was 24 years ago (McKay and Radziszowski, 1995). Since that time, the most sought number has been R(5,5). In the first part of the talk we will show a new computational approach that improves the upper bound to R(5,5) to 48 and maybe even to 47. In the second part of the talk we will show how subgraph identities combined with linear programming can be used to improve the known upper bounds on R(s,t) for many larger values of s and t.
Plaats: S9, lecture room 3.1
Organisator: Jan Goedgebeur

Datum: 1/7/2019 Tijd: 22:15 - 23:10	Campus Cup Morgen (1/7) neemt het team van de wiskunde het in de Campus Cup (op Canvas) op tegen het team van de Politieke Wetenschappen UGent ... Op naar de halve finale?
Plaats: TV
Organisator: Canvas

Datum: 27/6/2019 Tijd: 14:45	Financial Models with Jumps: Hedging in Exponential Lévy Models Verdediging van de masterproef Financial Models with Jumps: Hedging in Exponential Lévy Models door Lucas Slegers (promotor: Michèle Vanmaele).
Plaats: S9, leslokaal 3.2
Organisator: Opleiding wiskunde

Datum: 27/6/2019 Tijd: 14:00	Het prijzen van basket- en regenboogopties Verdediging van de masterproef Het prijzen van basket- en regenboogopties door Jannes Braet (promotor: David Vyncke).
Plaats: S9, leslokaal 3.2
Organisator: Opleiding wiskunde

Datum: 27/6/2019 Tijd: 10:00	Combinatorische eigenschappen van extremale veralgemeende zeshoeken Verdediging van de masterproef Combinatorische eigenschappen van extremale veralgemeende zeshoeken door Frédéric Verduyn (promotor: Bart De Bruyn).
Plaats: S25, Emmy Noether
Organisator: Opleiding wiskunde

Datum: 21/6/2019 Tijd: 11:00	Mean-value theorems for arithmetic functions and applications to Beurling numbers Verdediging van de masterproef Mean-value theorems for arithmetic functions and applications to Beurling numbers door Frederick Maes (promotor: Jasson Vindas).
Plaats: S8, leslokaal 0.1
Organisator: Opleiding wiskunde

Datum: 21/6/2019 Tijd: 11:00	Extending natural effect models to enable mediation analysis of correlated data Verdediging van de masterproef Extending natural effect models to enable mediation analysis of correlated data door Hege Michiels (promotor: Stijn Vansteelandt).
Plaats: S9, 3.1
Organisator: Opleiding wiskunde

Datum: 19/6/2019 Tijd: 14:30	Geometrische en fysische aspecten in verband met Poissonvariëteiten Verdediging van de masterproef Geometrische en fysische aspecten in verband met Poissonvariëteiten door Louise Arno (promotor: Jasson Vindas, copromotor: Frans Cantrijn).
Plaats: S8, leslokaal 3.2
Organisator: Opleiding wiskunde

Datum: 19/6/2019 Tijd: 14:00	Onderzoek van enkele meetkundes bepaald door axioma's Verdediging van de masterproef Onderzoek van enkele meetkundes bepaald door axioma's door Elisabeth Heyrman (promotor: Hendrik Van Maldeghem).
Plaats: S25, Emmy Noether
Organisator: Opleiding wiskunde

Datum: 14/6/2019 Tijd: 16:00	Tits Polygons and Long Root Geometries Verdediging van de masterproef Tits Polygons and Long Root Geometries door Paulien Jansen (promotor: Hendrik Van Maldeghem).
Plaats: JLU Giessen
Organisator: Opleiding wiskunde

Datum: 13/6/2019 Tijd: 11:00	Partiële spreads en bedekkingen van eindige projectieve ruimten en eindige klassieke polaire ruimten Verdediging van de masterproef Partiële spreads en bedekkingen van eindige projectieve ruimten en eindige klassieke polaire ruimten door Elke Lamberts (promotor: Leo Storme).
Plaats: S8, 2.2
Organisator: Opleiding wiskunde

Datum: 13/6/2019 Tijd: 10:00	Cameron-Liebler sets in affine geometries Verdediging van de masterproef Cameron-Liebler sets in affine geometries door Jonathan Mannaert (promotor: Leo Storme).
Plaats: S8, 2.2
Organisator: Opleiding wiskunde

Datum: 12/6/2019 Tijd: 12:00	Recent advances in Lie theory and Clifford algebras 12:00 – 12:50 Registration and lunch 12:50 – 13:00 Welcome and introduction Hendrik De Bie (UGent) 13:00 – 13:50 TBA Michael Ruzhansky(UGent) 13:50 – 14:40 Generalized Fourier transforms arising from dual pairs. Jing-Song Huang (Hong Kong University of Science and Technology) 14:40 – 15:00 Coffee break 15:00 – 15:50 Geometrical aspects of non-formal deformation quantization Pierre Bieliavsky (UCLouvain) 15:50 – 16:40 Representation theory and several Clifford variables. Roman Lávička (Charles University in Prague) 16:10 Closing
Plaats: S8, room 3.1
Organisator: Hendrik De Bie

Datum: 12/6/2019 Tijd: 10:00	Riemann oppervlakken Verdediging van de masterproef Riemann oppervlakken door Astrid De Brauwer (promotor: Hans Vernaeve).
Plaats: S8, lokaal 3.2
Organisator: Opleiding wiskunde

Datum: 12/6/2019 Tijd: 9:30	Automorfismengroepen van transcendente velduitbreidingen Verdediging van de masterproef Automorfismengroepen van transcendente velduitbreidingen door William Hautekiet (promotor: Tom De Medts).
Plaats: S25, lokaal Bourbaki
Organisator: Opleiding wiskunde

Datum: 7/6/2019 Tijd: 14:30	: Representation theory and cellular structure of seam algebras The seam algebras were introduced by Morin-Duchesne, Rasmussen and Ridout (2015) in order to introduce an adequate algebraic framework for the lattice analysis in Kac modules and their continuum limit counterpart, the Virasoro-Kac modules. They were viewed there as quotients of one-boundary Temperley-Lieb algebras and they were proven semisimple for generic value of the loop fugacity were given. It was known that they could also be obtained from classical Temperley-Lieb algebra by acting with a family of idempotents. Using this fact, we constructed a cellular basis for the seam algebra by exploiting the properties of a restriction functor and > found complete sets of irreducible and principal modules for all the > non-semisimple cases, except for one elusive family. This is joint work with Yvan Saint-Aubin
Plaats: room 3.2, S8
Organisator: Alexis Langlois Rémillard

Datum: 3/6/2019 Tijd: 14:00	Finite topological spaces in algebraic topology Verdediging van de masterproef Finite topological spaces in algebraic topology door Jens Renders (promotor: Koen Thas).
Plaats: S25, lokaal Bourbaki
Organisator: Opleiding wiskunde

Datum: 24/5/2019 Tijd: 14:30	Bargmann-Radon transform for axially monogenic functions In our work, we study a class of monogenic functions called axially monogenic functions. First we present the explicit form for the general Cauchy-Kowalewski extension for axially monogenic functions. Then we determine the Bargmann-Radon transform for these functions, relying on Funk-Hecke theorem in the process.
Plaats: room 3.2, S8
Organisator: Ren Hu

Datum: 10/5/2019 Tijd: 14:30	Modelling point cloud data: an approach from topology Topological data analysis (TDA) is an approach to the analysis of datasets, usually data point cloud, using techniques from topology. When data is high-dimensional, incomplete and noisy, TDA provides a general framework for analysis based on independence from the specific metric, dimensionality reduction and robustness to noise. Its main tool is persistent homology which computes, studies and encodes efficiently multiscale topological features from a nested families of simplicial complexes and topological spaces and finds applications in biology, chemistry and material science. Contemporary research is focusing on how to adapt its features for deep learning
Plaats: s8, 3.2
Organisator: Nicolas Vercheval

Datum: 3/5/2019 Tijd: 14:30	Discrete heat equations Many research has been devoted to the study of the heat equation, as this partial differential equation finds applications is amongst others physics, probability theory and financial mathematics. Our aim is to discretise this equation in the discrete Clifford framework in one dimension. We will consider both discrete space and discrete time. We determine a fundamental solution and investigate its properties. Discrete heat polynomials are constructed: discrete polynomial solutions p_n(x,t) of the heat equation with initial conditions p_n(x,0) = xi^n[1](x), where the latter is the basic discrete homogeneous polynomial. The amalogue problem in dual space is discussed
Plaats: s8, 3.2
Organisator: Astrid Massé

Datum: 26/4/2019 Tijd: 14:30	Segal-Bargmann transformations on superspaces The classical Segal-Bargmann is an integral transform between the Schrödinger space of square-integrable functions and the Fock space of holomorphic functions. In recent works the Segal-Bargmann transform was reinterpreted as an intertwining operator between realisations on the Schrödinger and the Fock space of the minimal representation of a Lie algebra. In this talk I will give a generalisation of this approach to superspaces in order to obtain a Segal-Bargmann transform as an integral transform that intertwines the Schrödinger and Fock model for the orthosymplectic Lie superalgebra osp(p,2|2n)
Plaats: room 3.2, S8
Organisator: Sam Claerebout

Datum: 5/4/2019 Tijd: 15:00	Polynomial representations of osp(1|2n). The well-studied boson Fock representation of osp(1|2n) can be easily realized in terms of partial derivatives and variable multiplications on the space of n-variable complex valued polynomials. Generalizing this situation by substituting the partial derivatives with p-dimensional Dirac operators and the variable multiplications with corresponding Clifford operators acting on spinor-valued polynomials, we get realizations of the paraboson representations of osp(1|2n) with lowest weight (p/2,...,p/2). Using a nice description of the characters of these representations in terms of Schur functions, we find natural bases of spinor-valued polynomials indexed by semi-standard Young tableaux.
Plaats: s8, 3.2
Organisator: smus Bisbo

Datum: 5/4/2019 Tijd: 14:30	The higher rank q-Bannai-Ito algebra and multivariate (-q)-Racah polynomials The q-Bannai-Ito algebra is a quadratic quantum algebra with remarkable properties. It encodes the bispectrality of the (-q)-Racah polynomials, which are the most fundamental orthogonal polynomials of q-hypergeometric type. In this talk, I will explain how this connection can be generalized to multiple variables. We will exploit the Hopf algebraic structure of quantum groups to build a higher rank extension of the q-Bannai-Ito algebra. We will study its action on the discrete series representation of the corresponding quantum group, and identify a class of canonical bases. Several such bases are in duality, in the sense that their overlap coefficients can be expressed as multivariate (-q)-Racah polynomials. The bispectral operators for these polynomials give rise to a discrete realization of the higher rank q-Bannai-Ito algebra.
Plaats: s8, 3.2
Organisator: Hadewijch De Clercq

Datum: 4/4/2019 Tijd: 17:30 - 19:00	Prof. Karen Uhlenbeck : Abel Prize winner 2019 Currently Prof. Mihaela Vajiac, one of her former postdocs and co-authors, is visiting the Clifford Research Group at Ghent University. Therefore the Mathematics Program at Ghent University is organizing the present event for students (bachelor, master and phd students) to inform them on the Abel Prize, to bring them in contact with a former close collaborator of the winner and to raise awareness on the topic of Women in Mathematics. The presentations will be mostly non-technical and in English. Program: 1. Introduction to the Abel Prize 2. Video projection on the Prize announcement and Laudatio of Karen Uhlenbeck 3. Work and impressions of Karen Uhlenbeck (Prof. Mihaela Vajiac, Chapman University) 4. Q&A session
Plaats: S9, A0
Organisator: prof. Hendrik De Bie

Datum: 3/4/2019 Tijd: 12:45 - 16:30	EOS Workshop 12:45 – 13:20 Registration and lunch 13:20 – 13:30 Welcome and introduction Hendrik De Bie (UGent) 13:30 – 14:20 Integration over (m-k)-surfaces using distributions and applications. Ali Guzmán Adán (UGent) 14:20 – 15:10 s-Regular Functions of a Quaternionic Variable which Preserve either One or All Slices Chiara de Fabritiis (Università Politecnica delle Marche, Italy) 15:10 – 15:20 Coffee break 15:20 – 16:10 Harmonic Maps, Riemann-Hilbert Problems and Virasoro actions Mihaela Vajiac (Chapman University, USA) 16:10 Closing
Plaats: s8, 3.1
Organisator: Prof. Hendrik De Bie

Datum: 29/3/2019 Tijd: 14:30	: Shadowing effect of multi-particle catalyst systems in TAP pulse experiments Abstract: Catalysts are the workhorses of chemical transformations in the industry. They offer often a green alternative path for reactions, favored by reduced activation energy but following a more complex path. Temporal Analysis of Products (TAP) is a pulsed transient technique able to extract intrinsic kinetic data of this complex path over a catalyst from reaction-transport data. Since the configuration of the catalyst could be shrunk to a single micron-sized catalyst particle, the characteristics of multi-particle systems for TAP are of interest. A shadowing effect has been studied by modeling the TAP reactor with a parabolic partial differential equation (PDE). First results will be shown solving the PDE with a Monte Carlo method and the finite element method.
Plaats: room 3.2
Organisator: Brecht Denis

Datum: 28/3/2019 Tijd: 19:30	Jobbeurs Jobbeurs voor wiskundigen, fysici en informatici met steun van de opleidingen wiskunde, informatica en fysica en sterrenkunde. Zie ook https://www.dropbox.com/s/10grh1lltul9x0o/JobavondAffiche.pdf?dl=0
Plaats: S25, Emmy Noether
Organisator: Prime, Wina, VVN en Zeus

Datum: 28/3/2019 Tijd: 14:30	MATHEMATICAL MODELING OF PHENOMENA OF WATER WAVE SCATTERING BY AN OBSTACLE MATHEMATICAL MODELING OF PHENOMENA OF WATER WAVE SCATTERING BY AN OBSTACLE Sudeshna Banerjea Department of Mathematics Jadavpur University Kolkata, India Abstract: Propagation of water waves in presence of an obstacle under the assumption of linearised theory will be studied mathematically. Starting from the basic hydrodynamic theory, the physical problem will be reduced to a boundary value problem. The solution of the boundary value problem will be discussed using the theory of integral equations.
Plaats: Gebouw S9, leszaal 1.1
Organisator: Van Daele Marnix

Datum: 21/3/2019 Tijd: 17:00	voordracht door prof. Kobayashi op 21 maart naar aanleiding van de uitreiking van eredoctoraten op 22 maart Origins and Future Perspectives of Performance Evaluation of Computers and Communication Networks. To be presented at Ghent University, Belgium on March 21, 2019 Hisashi Kobayashi2 Abstract: Performance evaluation of computers and communication networks has been an active and fertile field of research since the early 1970s. First, I would like to provide a brief historical overview of how this field has evolved during the past few decades. Queuing theory, pioneered by Agner Krarup Erlang (1878-1929), a Danish engineer, mathematician and statistician, has established itself as a branch of applied probability, and has played an important role in analytical methods for system performance evaluation. Then I discuss some problems and challenges in the current state of affairs in performance evaluation. They are related in part to the fact that hardware resources such as processors and storage have become astonishingly cost/performance efficient, and an increasingly larger portion of system design has become “software defined.” Thus, system developers today do fast prototyping and implementation, often skipping the performance analysis or prediction. Moreover, the gap between theory and practice in performance evaluation has widened considerably. In the final part of this talk, I will speculate on the future directions of performance evaluation and on possible opportunities for researchers in this field. Although the IP-based Internet has proven to be surprisingly robust, I foresee that an increasing level of video traffic and the forthcoming IoT (Internet of Things) will soon place huge workloads on the Internet, whose performance will become a serious issue in system design and operations. Researchers who are well versed in probability and statistics will find opportunities in emerging interdisciplinary areas involving machine learning, and big data analytics. Google’s search engine, for instance, adopts a computationally efficient procedure to find a stationary distribution of a certain Markov chain. A recent breakthrough in AI is ascribed to a “deep learning” neural network, which is intrinsically probabilistic and statistical. My instinct suggests that a “marriage” between performance evaluation and AI will be fruitful in tackling problems of complex system design and operations. Reference: Hisashi Kobayashi, Brian L. Mark and William Turin, Probability, Random Processes and Statistical Analysis, Cambridge University Press, 2012. 1 An earlier version of this talk was given at the QTNA 2018 held at Tsukuba City, Japan in July 2018. http://infoshako.sk.tsukuba.ac.jp/~tuan/qtna2018/ 2 The Sherman Fairchild University of Electrical Engineering and Computer Science, Emeritus, and a former Dean of the School of Engineering and Applied Science, Princeton University, Princeton, New Jersey 08544, USA Email: Hisashi@Princton.EDU Home page: http://hp.hisashikobayashi.com/
Plaats: Paviljoen Charles Vandenhove, Centrum voor Architectuur en Kunst
Organisator: H. Bruneel

Datum: 19/3/2019 Tijd: 16:00	OCW-cafe: informatiesessie n.a.v. Peer-leerbezoek Op 21 maart vindt het Peer-leerbezoek van de Opleiding Wiskunde plaats. Naar aanleiding hiervan zal ik een informatiesessie organiseren op dinsdag 19 maart om 16u00 in de multimediazaal. Ik maak er (naar het voorbeeld van de sessie in september 2017) terug een OCW-cafe van. Ik nodig op deze sessie ook de studenten uit die deelnemen aan het Peer-leerbezoek. Mag ik daarom aan de lesgevers vragen dat de eventuele lessen die in de opleiding wiskunde gepland zijn op zowel dinsdag 19 maart om 16u00 als op donderdag 21 maart tussen 13u00 en 14u30, verschoven zouden worden? Met vriendelijke groeten, prof. M. Van Daele OCW-voorzitter
Plaats: Multimetidazaal, S9
Organisator: OCW

Datum: 15/3/2019 Tijd: 14:30	The blocks of the periplectic Brauer algebra in positive characteristic Representation theory of the symmetric group can be related to representation theory of the general linear group via Schur-Weyl duality. Similarly, Schur-Weyl duality also relates the orthogonal Lie group, the symplectic Lie group and the encompassing orthosymplectic Lie supergroup to the Brauer algebra, and it relates the periplectic Lie supergroup to the periplectic Brauer algebra. In this talk I will introduce this periplectic Brauer algebra and give a classification of its blocks in positive characteristic. This is joint work with Anton Cox and Maud De Visscher.
Plaats: s8, 3.2
Organisator: Sigiswald Barbier

Datum: 1/3/2019 Tijd: 14:30	zie tekst David Eelbode (University of Antwerp) Title: The Cayley-Dirac operator on oriented Grassmannians (joint work with Yasushi Homma and Tim Janssens) In his PhD thesis, Tim Janssens has studied a differential operator which we have dubbed the Cayley-Dirac operator, for the simple reason that it factorises the so-called Cayley-Laplace operator (which has been studied in the past). Much to our surprise, these operators nicely generalise some properties from the classical case (harmonic/Clifford analysis in one vector variable) to a new setting, in which one essentially considers a suitable oriented Grassmannian instead of a sphere as the underlying 'basic manifold'. During this talk, we would like to highlight a few of these facts: we will start from the Howe duality for a certain function space, and see how far we can go with that. Güner Muarem (University of Antwerp) Title: Symmetries of differential operators and the Fueter theorem It is well-known that the quaternions discovered by Hamilton in 1843 form a number system that extends the complex numbers. An obvious first reflex in that time was to mimic the techniques and results from complex analysis in order to obtain a similar function theory. The first step was to find the correct analogue of the notion of holomorphic in the quaternionic setting: the so-called Fueter regularity. In this context the Swiss mathematician Fueter [1935] found a way of producing regular functions from holomorphic ones. One can now extend these notions and results to the general context of Clifford analysis: a function theory studying the so-called Dirac operator and its solutions(called monogenics) that is both a generalization of complex and Harmonic analysis (i.e. the function theory associated to the Laplace operator) but is also a refinement. In this talk we shall explain how the Fueter theorem can be proven in Clifford algebra context by using a representation theory inspired approach. This approach shall be closely related to (generalized) symmetries of given differential operators and their induced Lie algebraic structure. Furthermore, we shall generalize these results even more for symplectic Clifford algebras, something that was still missing in the existing literature and explore the connection with special functions.
Plaats: room 3.2, S8
Organisator: Clifford Analyse