Tag: combinatorics

The Domino problem on rhombus-shaped tiles.

-- Benjamin Hellouin de Menibus (LISN, Galac)

summary: The word tiling is a name for several models: geometrical tilings, where you tile the plane with geometrical shapes like a jigsaw puzzle; and symbolic tilings, where you tile the plane while matching colors on the edges of tiles. You can use both kinds of constraints; a well-known example ...

Une généralisation de la correspondance RSK via des représentations de carquois (de type A)

-- Benjamin Dequene (UQAM)

La correpondance de Robinson-Schensted-Knuth est une bijection partant des matrices d'entiers naturels vers les paires de tableaux de Young semi-standards. Une version généralisée donne une bijection entre des remplissages d'un tableau d'une certaine forme, et les partitions planes renversés de la même forme.

D'un point de ...

Column-convex {0,1}-matrices, consecutive coordinate polytopes and flow polytopes

-- Rafael S. González D'León (Loyola univ. Chicago) (LIX)

We study normalized volumes of a family of polytopes associated with column-convex {0,1}-matrices. Such a family is a generalization of the family of consecutive coordinate polytopes, studied by Ayyer, Josuat-Vergès, and Ramassamy, which in turn generalizes a family of polytopes originally proposed by Stanley in EC1. We prove ...

Games on Tilings

-- Rémi Pallen (LISN, Galac)

summary: Given a finite set A of colors and a finite set of target
patterns F, to know if one can tile the infinite grid avoiding
patterns in F is the domino problem. This problem can be seen as a
one-player game, where the goal for the player is to ...

Modular Automata Networks

-- Pacôme Perrotin (LISN, Galac)

summary: Automata networks are finite dynamical systems used to model gene regulatory networks. In this talk we talk about the difficult task of characterizing their limit behavior, and explore the formalism of modules which aims to simplify some of the technicalities related to those tasks.

A simple counting argument applied to lower bounds on the growth of subshifts

-- Matthieu Rosenfeld (LIRMM (Montpellier))

summary: Given a group G, a set of colors A and a set of forbidden patterns F, the subshift X_F is the set of colorings of G by A that avoid the patterns in F. I recently obtained a simple condition on the set of forbidden patterns F that implies ...

Coordonnées explicites pour le s-permutoèdre

-- Eva Philippe (IMJ) (LIX)

En 2019, Viviane Pons et Cesar Ceballos ont introduit une généralisation de l'ordre faible avec un paramètre s qui est un vecteur d'entiers. Ils ont conjecturé (et prouvé en dimensions 2 et 3) que cette structure admettait une réalisation géométrique comme complexe polytopal. En collaboration avec Daniel Tamayo ...

Algorithmes de partitionnement par comparaison de paires

-- Élie de Panafieu (Nokia Bell Labs) (LIX)

On cherche à reconstruire une partition d'un ensemble donné en envoyant des paires d'éléments à un oracle qui nous indique s'ils appartiennent à la même partie de la partition. Nous cherchons les algorithmes qui retrouvent la partition en un minimum de questions à l'oracle. Ce problème ...

Language-theoretic methods in semigroup theory

-- Carl-Fredrik Nyberg Brodda (Université Gustave Eiffel) (LIX)

Language-theoretic methods in combinatorial group theory go back to the fundamental work by Anisimov in the 1970s. Since then, the area has exploded, including such deep theorems as the Muller-Schupp theorem: a group has context-free word problem if and only if it is virtually free. In this talk, I will ...

The Domino Snake Problem

-- Nicolás Bitar (LISN, Galac)

summary: Deep within the swamp of undecidability lies the elusive domino snake. This species, first discovered in the 1970s by Myers, was originally introduced as an a priori simpler problem than the now celebrated Domino Problem. In this talk we will take a tour through what is known about this ...

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