Hông Van Lê (Czech Academy of Science, Czech Republic) will speak in the geometry seminar on the 19th December. The talk will take place in the Salle de Profs (9th floor, NO) at 13.30pm. Hông’s title is *“Novikov homology and Novikov fundamental groups”* and the abstract is below.

Novikov homology has been introduced by Novikov in the early 1980s motivated by problems in hydrodynamics. The Novikov inequalities in the Novikov homology theory

give lower bounds for the number of critical points of a Morse closed $1$-form on a compact differentiable manifold $M$. In the first part of my talk I shall survey the Novikov homology theory in finite dimensional setting and its further developments in infinite dimensional setting with applications in the theory of symplectic fixed points and

Lagrangian intersections/embeddings problems. In the second part of my talk I shall report on my recent joint work with Jean-Francois Barraud and Agnes Gadbled on construction of the Novikov fundamental group associated to a cohomology class of a closed 1-form on $M$ and its application to obtaining new lower bounds for the number of critical points of a Morse $1$-form.