La journée des nouveaux recrutés aura lieu au Laboratoire de mathématiques Jean Leray.

Programme :

9h00 - 9h15 -> Accueil

9h15 - 9h45 -> Yves De Cornulier (LMJL)
titre : Sur le groupe des échanges de rectangles
9h45 - 10h15 -> Tristan Bozec (LAREMA)
titre : Lieux critiques et structures algébriques sous-jacentes
10h15-10h45 -> Martin Averseng (LAREMA)
titre : Méthode des éléments finis appliquée à la propagation d'ondes haute-fréquence : des maillages non-uniformes définis par la dynamique des rayons.

10h45 - 11h15 -> Pause

11h15 -11h45 ->  Yann Chaubet (LMJL)
titre : Comptage des géodésiques fermées des surfaces
11H45 - 12H15 ->  Nicolina Istrati (LAREMA)
titre : Géométrie localement conformément kählerienne

12h30 - 14h00 -> Buffet végétarien

14h15 - 14h45 -> Benjamin Dadoun (LMM)
titre : Monotonie d'une énergie logarithmique pour les matrices aléatoires
14h45 - 15h15 ->  Corentin Lothodé (LAREMA)
titre : Différentes approches numériques pour le calcul haute-performance.

15h15 - 15h45 -> Pause

15h45 - 16h15 ->  Massimo Pippi (LAREMA)
titre : Géométrie arithmétique et géométrie non commutative
16h15 - 16h45 ->  Dorian Le Peutrec (LMJL)  
titre : Approche spectrale de diffusions métastables

10h30-11h30 - Andras Stipsicz (Reny Institut Budapest)
"Z_2-actions on four-manifolds"

Abstract:
Exotic smooth structures on four-manifolds are one of the most surprising, and at the same time most fascinating phenomena in low dimensional topology. Existence questions of exotic smooth structures on closed simply connected four-manifolds with definite intersection form are of central importance — as a special case, this problem includes the smooth four-dimensional Poincaré conjecture.
We show exotic examples of definite four-manifolds with fundamental group Z_2.
In another direction, Z_2-actions on specific exotic four-manifolds provide embeddings of connected sums of the real projective plane RP^{^2} to the four-sphere S^{^4} which are topologically standard, but smoothly not.
Smooth exotica are proved using Seiberg-Witten theory — we will hint the use of these invariants in this context.

14h00-15h00 - Vincent Florens (Université de Pau)
"Topological invariants of line arrangements"

Abstract:
A line arrangement is a finite set of lines in the complex projectiveplane CP2. They are  particular cases of plane algebraic curves where the components have all degree 1. We are interested in the influence of the combinatorial data of an arrangement on its embedded topology in CP2.
The boundary manifold of an arrangement is the common boundary of a regular neighborhood of the arrangement and its exterior. This is a graph three-manifold, in the sense of Waldhausen, whose topology is completly determined by the combinatorics. We use the inclusion map of the boundary manifold in the exterior to construct a new topological invariant of arrangements. This is a joint work with E.Artal and A.Rodau.

15h30-16h30 - Discussions

10h30-11h30 - Andras Stipsicz (Reny Institut Budapest)
"Z_2-actions on four-manifolds"

Abstract:
Exotic smooth structures on four-manifolds are one of the most surprising, and at the same time most fascinating phenomena in low dimensional topology. Existence questions of exotic smooth structures on closed simply connected four-manifolds with definite intersection form are of central importance — as a special case, this problem includes the smooth four-dimensional Poincaré conjecture.
We show exotic examples of definite four-manifolds with fundamental group Z_2.
In another direction, Z_2-actions on specific exotic four-manifolds provide embeddings of connected sums of the real projective plane RP^{^2} to the four-sphere S^{^4} which are topologically standard, but smoothly not.
Smooth exotica are proved using Seiberg-Witten theory — we will hint the use of these invariants in this context.

14h00-15h00 - Vincent Florens (Université de Pau)
"Topological invariants of line arrangements"

Abstract:
A line arrangement is a finite set of lines in the complex projectiveplane CP2. They are  particular cases of plane algebraic curves where the components have all degree 1. We are interested in the influence of the combinatorial data of an arrangement on its embedded topology in CP2.
The boundary manifold of an arrangement is the common boundary of a regular neighborhood of the arrangement and its exterior. This is a graph three-manifold, in the sense of Waldhausen, whose topology is completly determined by the combinatorics. We use the inclusion map of the boundary manifold in the exterior to construct a new topological invariant of arrangements. This is a joint work with E.Artal and A.Rodau.

15h30-16h30 - Discussions