Tiling Groups: Emptiness and Aperiodicity
summary: Tilings of the plane or infinite grid have been a rich field of study for many years. Through tiling with local rules, it is even possible to create aperiodicity and embed computation in the plane. But what happens when we begin changing the underlying structure? We will explore how ...
Vingt mille lieues sous les mots
summary: Dans cette présentation, nous découvrirons une partie de l'écosystème de l'océan de la combinatoire de mots, dont l'exploration a commencé depuis plus d'un siècle. À la surface vivent d'abord les mots périodiques, aux propriétés très régulières et simples : ils nous serviront de point d ...
Introduction à l'apprentissage par renforcement
summary: Cet exposé proposera une introduction à l'apprentissage par renfocement, en présentant les fonctions à maximiser et les types d'approches employées. La présentation suivra l'évolution historique du domaine, du Q-Learning au Deep Reinforcement Learning, en passant par des travaux étant devenus populaires tel que AlphaGo. Nous conclurons ...
Strong local rules without labels for Penrose rhombus tilings
summary: The Penrose rhombus tilings are a subshift of tilings of the planefirst defined by R. Penrose. This subshift is crucial in the study of geometrical tilings because, though it was originally defined with 2 rhombus tiles with cuts-and-notches or arrows on the edges, it is an aperiodic subshift with ...
Multitriangulations and tropical Pfaffians
The \(k\)-associahedron \(Ass_k(n)\) is the simplicial complex of \((k+1)\)-crossing-free subgraphs of the complete graph with vertices on a circle. Its facets are called \(k\)-triangulations. We explore the connection of \(Ass_k(n)\) with the Pfaffian variety \(Pf_k(n)\subset K^\binom{n}{2}\) of antisymmetric matrices ...
Efficient generation of rectangulations and elimination trees via permutation languages
In this talk we apply the Hartung-Hoang-Mütze-Williams permutation language framework to derive exhaustive generation algorithms for two further classes of combinatorial objects, as well as Hamilton paths and cycles on the corresponding polytopes: (3) different classes of rectangulations, which are subdivisions of a rectangle into smaller rectangles (see www.combos ...
Combinatorial generation via permutation languages
In this talk we present a versatile algorithmic framework for exhaustively generating a large variety of different combinatorial objects, based on encoding them as permutations. This framework provides a unified view on many known Gray code results and allows us to prove many new ones, and it yields efficient algorithms ...
Enumération des cartes planaires à trois bords par découpage en tranches
Parmi toutes les techniques d’énumération des cartes planaires (graphes plongés sur la sphère à deux dimensions), une des approches conceptuellement les plus simples et directes consiste à découper la carte en tranches: si on dispose d’une règle canonique de découpage et que les tranches ainsi obtenues sont faciles ...
Self-Stabilization and Byzantine Tolerance for Maximal Independent Set
summary: We analyze the impact of transient and Byzantine faults on the construction of a maximal independent set in a general network. We adapt the self-stabilizing algorithm presented by Turau for computing such a vertex set. Our algorithm is self-stabilizing, and also works under the more difficult context of arbitrary ...
A counting argument for graph colouring
summary: In 2010, Moser and Tardos introduced an algorithmic version of the celebrated Lovász Local Lemma using the entropy compression method. Their method is now widely used in the community and has become a standard of the probabilistic method, mainly because it often provides the tightest existential bounds. However, it ...