Skip to main content
Go to the home page of the European Commission (opens in new window)
English en
CORDIS - EU research results
CORDIS

Combinatorial and Geometric Methods for Mapping Class Groups of Surfaces

Project description

Exploring symmetries of topological surfaces

Symmetry is a key concept in mathematics, especially when studying complex objects like compact topological surfaces. The symmetries of these surfaces are described by the mapping class group, a central topic in topology. Supported by the Marie Skłodowska-Curie Actions programme, the MapSurf project explores the geometry of mapping class groups through simplicial graphs, with a focus on the pants graph. This graph is essential for understanding both the algebraic and geometric properties of surfaces and 3-manifolds. The project investigates the relationship between distances in the pants graph and surface decompositions, while addressing the computational complexities of calculating these distances.

Objective

Given a mathematical object, a common theme is to study the symmetries of that object. In this project, the objects are compact topological surfaces, and the group of symmetries is the mapping class group.

In this project, we will investigate simplicial graphs associated to surfaces, which have proved to be key tools in the study of both the algebraic and the geometric structure of mapping class groups. Studying the geometry of groups has proved to be a profound way to study their algebraic properties. We will focus on a graph called the pants graph, whose vertices represent pants decompositions of the surface (collections of homotopy classes of simple closed curves that cut the surface into spheres with three holes). The pants graph is significant not only in the study of mapping class groups, but also in studying the hyperbolic geometry of surfaces and 3-manifolds.

The first part of the project is to understand how distances between vertices in the pants graph are related to the number of intersections between the corresponding pants decompositions. For a related graph, the curve graph, it is known that the distance between two vertices is bounded above by a logarithmic function of the number of intersections, but the methods do not immediately generalise to the pants graph. We will also investigate questions of computational complexity around computing distances in the pants graph. This part of the project will include a secondment at a computer science department.

The second part of the project is to investigate maps from the pants graph to itself which preserve distances up to bounded error (such maps are called quasi-isometries). In a general metric space, the group of quasi-isometries is much bigger than the isometry group, but for most pants graphs, Bowditch proved that the two groups coincide, a property called quasi-isometric rigidity. We aim to prove that the same is true for three of the remaining unsolved cases.

Fields of science (EuroSciVoc)

Keywords

Programme(s)

Topic(s)

Funding Scheme

HORIZON-TMA-MSCA-PF-EF - HORIZON TMA MSCA Postdoctoral Fellowships - European Fellowships

See all projects funded under this funding scheme

Call for proposal

(opens in new window) HORIZON-MSCA-2022-PF-01

See all projects funded under this call

Coordinator

UNIVERSITE DU LUXEMBOURG
Net EU contribution
€ 175 920,00
Address
2 PLACE DE L'UNIVERSITE
4365 ESCH-SUR-ALZETTE
Luxembourg
Region
Luxembourg Luxembourg Luxembourg
Activity type
Higher or Secondary Education Establishments
Links
Total cost
No data

Partners (1)