The Floer homology: topology and differential equations

Floer’s homology has now established itself as a fundamental bridge between topology and the in-depth study of differential equations. Originating from the developments in symplectic geometry at the end of the 20th century, this theory has decisively changed the understanding of manifolds, particularly those of infinite dimension. Designed as an analogue of Morse theory in … Read more

The theory of deformations: continuous families of structures

The theory of deformations occupies a central place in the study of changes in shape within geometry and physics. It sheds light on how often complex structures can evolve based on notions of continuous families, topology, and differential geometry. The study of continuous families of structures allows for a better understanding of the gradual variations, … Read more

Ergodic theory: invariant measures and mixing

The ergodic theory opens fascinating perspectives beyond the traditional boundaries of mathematics and physics. This discipline focuses on the study of dynamical systems and how, over time, the trajectories of a system explore its entire state space. In particular, the key concepts of invariant measures, mixing, and ergodicity provide essential tools for understanding how seemingly … Read more

Integrable systems: solitons and transformations

Integrable systems embody a fascinating branch of physics and mathematics, revealing phenomena of rare elegance. Rooted in rigorous mathematical structures, these systems allow for the study of nonlinear waves and stable, recurrent solutions called solitons, which are observed in contexts as diverse as the propagation of light in optical fibers, ocean waves, or even quantum … Read more

Symplectic geometry: mechanics and differential forms

Symplectic geometry finds its roots in the equations of classical mechanics, revisited through a mathematical prism that combines rigor and geometric intuition. This discipline, born out of the need to formalize the dynamics of physical systems, particularly through Hamiltonian mechanics, relies on fundamental notions such as differential forms and symplectic varieties. From its early developments … Read more

The theory of singularities: catastrophes and deformations

The theory of singularities establishes itself as a powerful framework that sheds light on unexpected behaviors and sudden breaks encountered in complex dynamic systems. It clarifies phenomena where conventional mathematical models become insufficient, particularly when critical points cause drastic changes, referred to as catastrophes. This theory, which draws its roots from differential geometry and nonlinear … Read more

General topology: compact and connected spaces

General topology occupies a central place in mathematics by exploring the properties of spaces that remain invariant under continuous deformations. This discipline goes beyond simple classical geometry to study fundamental notions such as compactness, which ensures a form of “structural finiteness” in a space, or connectedness, reflecting the intuitive idea of “contiguity” or “absence of … Read more

The theory of sheaves: cohomology and geometry

A fundamental tool in modern mathematics, sheaf theory revolutionizes the way we understand spaces and their local and global properties. It closely connects topology, algebraic geometry, and homological algebra, offering a unifying language to explore complex objects where the interaction between local and global structures is crucial. The cohomology of sheaves, in particular, paves the … Read more

Model theory: logic and mathematical structures

Model theory occupies a central place in mathematical logic by providing a rigorous framework to interpret axiomatic theories through concrete mathematical structures. This powerful branch explores how formal languages can be translated into coherent systems where concepts such as satisfiability, truth, or isomorphism gain precise meaning. It develops essential tools for analyzing and classifying complex … Read more

Hyperbolic geometry: negative curvature and geodesics

Hyperbolic geometry intrigues as much as it challenges the intuitions anchored in Euclidean geometry. Diving into a universe where the classical rules of geometry no longer apply, it explores a space with negative curvature, a notion that upends the way we view lines, surfaces, and distances. At the beginning of the 21st century, this mathematical … Read more