GAGTA-9 : Geometric, Asymptotic and Combinatorial Group Theory and Applications
September 14 -18, 2015
The series of conferences named « GAGTA » is devoted to the confrontation of several viewpoints on the theory of infinite groups: geometric, combinatorial, asymptotic and probabilistic, algorithmic and computational. Topics discussed at these conferences include group actions; growth and isoperimetric functions and other asymptotic invariants; random walks; algebraic geometry on groups; algorithmic properties and their complexity; generic properties and more generally generic complexity; and applications of group theory, notably to non-commutative cryptography.

All these topics place the GAGTA conferences at a meeting point between algebra, topology and geometry, and more and more frequently, at a meeting point also with probability theory and asymptotic methods.

Many of the topics discussed at these conferences have deep roots in the classical theory of groups and especially its links with geometry. We can cite also, among the results or the theories that have played an important role in the genesis of the GAGTA conferences, M. Gromov’s results at the beginning of the 1980s, the solution of Tarski’s problem by Z. Sela and by A. Miasnikov and O. Kharlampovich, and more recently the theory of relatively hyperbolic groups developed by M. Gromov, Yu. Ol’shanskii, D. Osin and other mathematicians.

The 2015 edition of the conference, the ninth GAGTA and the first to be held in France, will of course rely on the fundamentals of the series; but it will additionally give a special emphasis to the contributions of asymptotic theory; the algorithmic aspects of group theory; and its connections with computer science.

Scientific Committee

Goulnara Arzhantseva (University of Vienna)
Laurent Bartholdi (University of Göttingen)
Patrick Dehornoy (Université de Caen & Université Paris-Diderot)
Anna Erschler (Université Paris-Sud)
Olga Kharlampovich (Hunter College, CUNY)
Vincent Guirardel (Université Rennes 1)
Enric Ventura (UPC Barcelona)

Organizing Committee

Thierry Coulbois (Aix-Marseille Université)
Pascal Weil (Université Bordeaux 1)


Almost commuting permutations are near commuting permutations

Random graphs and applications to Coxeter groups

Solubility and geometry for finitely generated groups of piecewise-linear homeomorphisms

  • Pep Burillo (University ‘Politècnica de Catalunya’)
  • Montserrat Casals-Ruiz (University ‘Pais Vasco’)

Embeddability between right-angled Artin groups and its relation to model theory and geometry

Primitive elements in low-index subgroups of finitely generated groups

Formal conjugacy growth and hyperbolicity

Sofic profile

Multifraction reduction in gcd-monoids

Stallings foldings for Zm x Fn

EDT0L-like description of the solution sets for a word equations over RAAGs

Solution sets for equations over free groups are EDT0L languages

Groups with the property R infinite

The planar Cayley graphs are effectively enumerable

  • Torsten Groth (Georg August University of Göttingen)

Quadratic equations in self similar groups

Higher divergence functions for Heisenberg Groups

  • Arye Juhasz (Technion Israel Institute of Technology)

On a class of Artin groups

Conjugacy Problem in Polycyclic and Metabelian Groups: Algorithms and Complexity

On some classes of Coxeter- and Artin-like groups

On limit groups over partially commutative groups

Model Theory of groups and algebras

Path lifting properties and embedding between RAAGs

Induced automorphisms

Algorithmic double personality of finitely generated nilpotent groups

Substitutional dynamics associated with Grigorchuk’s group

Invariant random subgroups of acylindrically hyperbolic groups

From automatic semigroups to automaton semigroups

Hilbert’s Nullstellensatz in algebraic geometry over rigid solvable groups

CSA and CT groups and related topics

On subgroups of the R. Thompson group F

Semigroups of linear functions

Extending endomorphisms of hyperbolic groups to the boundary

Lattices, superrigidity and surfaces

The degree of commutativity of an infinite group

Probability of Generating the Symmetric Group

An analogue of the curve complex for Garside groups

  • Jianchun Wu (University ‘Politècnica de Catalunya’)

Fixed subgroups are compressed in surface groups

  • Wenyuan Yang (Beijing International Center for Mathematical Research)

Hausdor dimension of boundaries of relatively hyperbolic groups

  • Alexander Zakharov (University ‘Pais Vasco’)

Kurosh rank of intersection of subgroups in groups acting
on trees with nite edge stabilizers

Random walks on random symmetric groups