Local seminar

This is the webpage of the local seminar of the Discrete Math. team of ULiège. If you wish to pay us a little research visit, please contact either Antoine Abram, Antoine Renard, or Manon Stipulanti.

2026-2027

• September 16, 2026; Tore Koß (ULiège), TBA
• September 2, 2026: Lucía Rossi (Vienna Univ. of Technology), Triple points in tilings related to numeration systems
  Abstract: Given a polynomial Ax² + Bx + C with integer coefficients, we show how to define a numeration system whose basis is a complex root of this polynomial. This numeration system induces a tiling of the complex plane, and we want to study points that lie at the intersection of three tiles, which correspond to points with three distinct expansions. We give conditions on A, B and C to characterize when a given tile has at most 8 triple points, which is a measure of regularity for this tiling. We extend this result to shift radix systems. This is joint work with Shigeki Akiyama.

2025-2026

2024-2025

• June 19, 2025: Evgeny Verbitskiy (Leiden Univ.), Computation of Lyapunov exponents of matrix products
• June 5, 2025: Raphaël Henry (Aix-Marseille Univ.), Beyond minimal substitution subshifts
• May 28, 2025: Elise Vandomme (HEC Liège), Local stability of kidney exchanges with length-two cycles
• May 22, 2025: Vincente Saavadra (Univ. of Warwick), Uniform distribution of integers with digit restrictions
• May 12–16, 2025: Words and subwords workshop. Invited speakers: N. Rampersad, M. Stipulanti, N. Ollinger, G. Fici, B. Espinoza, M. Golafshan, M. Rosenfeld, R. Mercas, J.-P. Allouche, D. Jamet, J. Cassaigne, A. Huch, P. Popoli, M. Whiteland, W. Fang, G. Richomme, A. Renard, L. Renard, P. Schnoebelen, I. Vialard, M. Rigo
• May 8, 2025: Youssed Fares (LAMFA, Amiens), Autour de la conjecture de Ponen sur les polynômes quadratiques
• April 17, 2025: Reem Yassawi (Queen Mary Univ. of London), Algebraic power series and their automatic complexity modulo prime powers
• April 10, 2025: Andrew Mitchell (Univ. of Birmingham), Complexity of random subshifts
• March 20, 2025: Mehdi Golafshan (ULiège), Combinatorial complexity of words formed by leading digits of sequences
• March 12, 2025: Viviane Pons (Univ. Paris-Saclay), Le s-ordre faible et s-Permutaèdre
• February 20, 2025: Edouard Daviaud (ULiège), Diophantine appoximation on fractals
• February 6, 2025: Michel Rigo (ULiège), Automatic proofs in combinatorial game theory
• January 23, 2025: Henk Bruin (Univ. of Vienna), Ergodic properties of sums of visits to [0,1/2) by quadratic irrational rotations
• January 9, 2025: Julien Cassaigne (I2M, Aix-Marseille Université), Sur la complexité conjecturée de la suite d'Oldenburger-Kolakoski
• December 5, 2024: Pierre Stas (ULiège), Stability of return groups
• November 21, 2024: Wolfgang Steiner (CNRS, IRIF), Unique double expansions and binary shifts with a hole
• November 14, 2024: Olga Lukina (Leiden Univ.), Prime numbers in the dynamics on non-abelian odometers
• November 7, 2024: Slade Sanderson (Utrecht Univ.), Accelerating slow continued fractions
• October 17, 2024: Léo Vivion (LMPA, Univ. Côte d'Opale), propriétés abéliennes des mots de billiard hypercubiques
• October 3, 2024: Renan Laureti (ULiège), Construction of a normal number in continued fraction and Pisot bases

2023-2024

• June 13–14, 2024: Philipp Hieronymi (Universität Bonn), Logic, Numeration, Decidability
• May 24, 2024: Nicolas Ollinger (Université d'Orléans), Dumont-Thomas numeration systems for Walnut
• May 17, 2024: Virginie Debauche (UCLouvain), Comparison of path-complete Lyapunov stability certificates: characterization by template-dependent lifts
• April 19, 2024: Bastian Espinoza (ULiège), The stabilized automorphism group of low complexity subshifts
• April 11, 2024: Matthieu Rosenfeld (LIRMM, Université de Montpellier), Reconstructing words using queries on subwords or factors
• March 28, 2024: Jaime Gomez (Pontificia Universidad Católica de Chile), Topo-isomorphisms of irregular Toeplitz subshifts for residually finite groups
• March 14, 2024: Bernard Boigelot (ULiège), An automata-theoretic approach to the monadic first-order theory of order
• December 8, 2023: France Gheeraert (ULiège), A study of dendricity through the lens of morphisms
• December 1, 2023: Michael Baake (Universität Bielefeld), On some dynamical systems of number-theoretic origin
• November 24, 2023: Mélodie Andrieu (LMPA, Université Littoral Côte d'Opale), A generalization of the theorem of Morse and Hedlund
• November 10, 2023: Antoine Renard (ULiège), q-deformations of binomial coefficients of words
• October 27, 2023: Karma Dajani (Univ. Utrecht), The matching phenomenon
• October 20, 2023: Pierre Popoli (ULiège), Correlation of the Rudin-Shapiro sequence along prime numbers
• October 13, 2023: Bastien Laboureix (LORIA, Université de Lorraine), Connexité des hyperplans arithmétiques et systèmes de numération
• October 6, 2023: Nicolas Bitar (LISN, Université Paris-Saclay), Domino Snake Problems on Groups
• September 29, 2023: Herman Goulet-Ouellet (IRIF, Université Paris Cité), Obstructions to return preservation for episturmian morphisms
• September 22, 2023: Carole Porrier (LACIM, Université du Québec à Montréal & LIPN, Université Sorbonne Paris Nord), The Leaf Function of Penrose P2 Graphs
• September 15, 2023: Benjamin Hellouin de Menibus (LISN, Université Paris-Saclay), Asymptotic bahaviour of cyclic automata

2022-2023

• June 7, 2023: Joël Ouaknine (Max Planck Institute for Software Systems), The Skolem Landscape
• May 31, 2023: Felipe Arbulú (Université de Picardie Jules Verne), Dynamical properties of minimal Ferenczi subshifts
• May 10, 2023: Samuel Petite (Université de Picardie Jules Verne), Expansivité dans la dynamique topologique: une approche géométrique via le théorème de Robinson
• April 19, 2023: Julien Leroy (ULiège), Ergodic measures in eventually dendric shifts
• April 12, 2023: Markus Whiteland (ULiège), The gapped reconstruction problem and related complexity functions of words
• March 22, 2023: Pierre Guillon (CNRS, Aix-Marseille Université), Déterminisme symbolique en dynamique symbolique multidimensionnelle
• March 15, 2023: Savinien Kreczman (ULiège), Greedy numeration systems with a regular language
• March 8, 2023: Sebastián Barbieri (Universidad de Santiago de Chile), Self-simulable groups
• March 1, 2023: Michel Rigo (ULiège), Automaticity and Parikh-collinear morphisms
• February 15, 2023: Chistopher Cabezas (ULiège), Homomorphisms and decidable problems between multidimensional constant-shape substitution
  

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  2021-2022

• December 7, 2021: Bastian Espinoza (ULiège), Symbolic factors of minimal subshifts of finite topological rank
• September 21, 2021: Chistopher Cabezas (ULiège), Homomorphisms between multidimensional constant-shape substitutions

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2020-2021 (on-line local seminars due to Covid restrictions)

• June 3, 2021: Michel Rigo, On digital sequences associated with Pascal's triangle
• May 12, 2021: Samuel Nicolay
• May 5, 2021: France Gheeraert
• April 28, 2021: Marie Lejeune
• March 31, 2021: Julien Leroy, Factorization of minimal substitution subshifts
• March 24, 2021: Adeline Massuir
• March 17, 2021: Manon Stipulanti, Michel Rigo, Automatic sequences: from rational bases to trees
• February 24, 2021: Savinien Kreczman, Additive number theory via automata theory (project)
• February 17, 2021: Cécile Mammez, Algebraic structures on walks of graphs - Reconstruction of the identity
• February 10, 2021: Célia Cisternino, Dynamical properties of greedy and lazy alternate base expansions

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2019-2020

• February 19, 2020: Mirna Dzamonja (Univ. East Anglia, IHPST Paris), WQO et les arguments de terminaison
• December 6, 2019: Elise Vandomme (ULiège), Recurrence along directions in multidimensional words
• December 5, 2019: Jennifer McLoud-Mann (Univ. of Washington), Knots arising from saturated hexagonal mosaic patches
• November 27, 2019: Pamela Fleischmann (Univ. Kiel), Scattered Factor Universality of Words
• November 21, 2019: Edwin Hamel-de-le-court (Univ. Rouen), Algebraic tools for state complexity
• November 13, 2019: Karma Dajani (Univ. Utrecht), Sums of Cantor sets
• October 24, 2019: Victor Marsault (CNRS, Paris Est), Introduction to View-Based Query Processing
• October 4, 2019: Florian Liétard (Loria, Univ. Lorraine), Evitabilité des puissances additives

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2018-2019

• June 11, 2019: Lama Tarsissi (Paris Est), Digital convexity with combinatorics on words
• June 4, 2019: Reem Yassawi (IRIF, Université Paris Diderot), Versions quantitatives du théorème de Christol
• April 23, 2019: Guilhem Gamard (ENS Lyon), Quasipériodes des mots biinfinis
• April 3, 2019: small workshop following M. Stipulanti's PhD defense:
  • Raphaël Jungers (UCLouvain), A complete characterization of the ordering relation on path-complete stability criteria
  • Robbert Fokkink (TU Delft), Some personal intersections with intersections
  • Célia Cisternino (ULiège), Alternate basis, alternate expansions, and a generalization of Parry's theorem
  • Sébastien Labbé (CNRS, Bordeaux), Recent development on the understanding of Jeandel-Rao aperiodic tilings
  • Jean-Eric Pin (CNRS, IRIF), A Mahler's theorem for word functions
  • Adeline Massuir (ULiège), State complexity of the multiples of the Thue-Morse set
  • Marie Lejeune (ULiège), Computing the k-binomial complexity of the Tribonacci word
• March 19, 2019: Fransceco Dolce (IRIF, Paris), Generalized Lyndon words
• March 12, 2019: Manon Stipulanti (ULiège), The formal inverse of the period-doubling sequence
• February 26, 2019: Adeline Massuir (ULiège), Automatic sequences based on Parry or Bertrand numeration systems
• January 24, 2019: Célia Cisternino (ULiège), Complexité en états des écritures en base 2^p des multiples de l'ensemble de Thue-Morse
• January 10, 2019: Julien Leroy (ULiège), Decidability of the isomorphism and the factorization between minimal substitution subshifts
• December 20, 2018: Jérôme Leroux (CNRS, Bordeaux), Reachability problem for Petri nets is not elementary
• December 17, 2018: Matthieu Rosenfeld (ULiège), Avoiding squares over 3 letters using the power series method and application to the Thue list coloring number
• December 6, 2018: Marie Lejeune (ULiège), Calcul de la complexité k-binomiale du mot de Thue-Morse
• December 6, 2018: Catherine Dehon (ULB), Les impacts du décret "Paysage" sur les parcours étudiants et l'utilisation des learning analytics comme soutien à l'apprentissage
• November 29, 2018: Anne Ruiz-Gazen (Toulouse School of Economics), Invariant Coordinate Selection for outlier detection with application to quality control
• November 29, 2018: Michel Rigo (ULiège), Taking-and-merging games as rewrite games
• October 22, 2018: Robert Gaunt (Univ. of Manchester), Compound Poisson Approximation of subgraph counts in Stochastic block models
• October 4, 2018: Florian Liétard (LORIA, Univ. de Lorraine),
• October 3, 2018: Valentin Ovsienko (CNRS, Univ. de Reims), Fractions continues et triangulations; les nombres rationnels q-déformés

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2017-2018