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Ci-dessous, les différences entre deux révisions de la page.

--- fables [2021/12/09 16:09] – kalinin0
+++ fables [2023/03/23 03:24] – kalinin0
@@ Ligne 1: / Ligne 1: @@
 ====== Séminaire "Fables Géométriques". ======
-The normal starting time of this seminar is 16.30 on Monday.
+  Monday, March 27, 2023
+  room 6-13
+**16h00 — Sebastian Haney (Columbia U)**
+**Mirror Lagrangians to lines in P^3**
+We discuss work in progress in which we construct, for any tropical curve in R^n with vertices of valence at most 4, a Lagrangian submanifold of (C^*)^n whose moment map projection is a tropical amoeba. These Lagrangians will have singular points modeled on the Harvey-Lawson cone over a 2-torus. We also consider a certain 4-valent tropical curve in R^3, for which we can modify the singular Lagrangian lift to obtain a cleanly immersed Lagrangian. The objects of the wrapped Fukaya category supported on this Lagrangian correspond, under mirror symmetry, to lines in CP^3. If time permits, we will explain how to use functors induced by Lagrangian correspondences to see this mirror relation.
+----
+  Monday, March 20, 2023
+  room 6-13
+**16h00 — Ilia Itenberg (Sorbonne)**
+**Maximal real algebraic hypersurfaces of projective spaces**
+The talk is devoted to a combinatorial patchworking construction of maximal (in the sense of the generalized Harnack inequality) real algebraic hypersurfaces in real projective spaces (joint work with Oleg Viro).
+During the talk, we will mainly concentrate on the construction of a maximal quintic hypersurface in the 4-dimensional real projective space.
+----
+  Monday, March 6, 2023
+  room 6-13
+**15h00 — Ali Ulaş Özgür Kişisel (METU, Ankara)**
+**Expected measures of amoebas of random plane curves**
+There are several natural measures that one can place on the amoeba of an algebraic curve in the complex projective plane. Passare and Rullgård prove that the total mass of the Lebesgue measure on the amoeba of a degree $d$ curve is bounded above by $π^{2} d^{2} / 2$, by comparing it to another Monge-Ampère type measure, which is dual to the usual measure on the Newton polytope of the defining polynomial via the Legendre transform. Mikhalkin generalizes this upper bound to half-dimensional complete intersections in higher dimensions, by considering another measure supported on their amoebas; their multivolume. The goal of this talk will be to discuss these measures in the setting of random plane curves. In particular, I’ll first present our results with Bayraktar, showing that the expected multiarea of the amoeba of a random Kostlan degree $d$ curve is equal to $π^2 d$. For Lebesgue measure, it turns out that the expected asymptotics are much lower: I’ll describe our results with Welschinger, showing that the expected Lebesgue area of the amoeba of a random Kostlan degree $d$ curve is of the order $(\log d)^2.$
+----
+  Monday, February 27, 2023
+  room 6-13
+**15h00 — Evgeni Abakoumov (Paris/Eiffel U)**
+**Chui's conjecture аnd rational approximation**
+C. K. Chui conjectured in 1971 that the average gravitaional field strength in the unit disk due to unit point masses on its boundary was the smallest when these point masses were equidistributed on the circle. We will present an elementary solution to some weighted versions of this problem, and discuss related questions concerning approximation of holomorphic functions by simple partial fractions. This is joint work with A. Borichev and K. Fedorovskiy.
+**16h00 — Ferit Ozturk (Istanbul/Bosphorus U and Budapest/Renyi Inst)**
+**Every real 3-manifold admits a real contact structure**
+We survey our results regarding real contact 3-manifolds and present our result in the title.
+A real 3-manifold is a smooth 3-manifold together with an orientation preserving smooth involution, called a real structure.
+A real contact 3-manifold is a real 3-manifold with a contact distribution that is antisymmetric with respect to the real structure.
+The standard examples of real contact 3-manifolds are link manifolds of isolated, real analytic surface singularities.
+We show that every real contact 3-manifold can be obtained via contact surgery along invariant knots starting from the standard real contact 3-sphere.
+As a corollary we show that any oriented overtwisted contact structure on an integer homology real 3-sphere can be isotoped to be real.
+----
+  Monday, February 6, 2023
+:00, room 6-13
+**Sergey Finashin (Ankara)**
+**“Affine Real Cubic Surfaces”**
+Abstract: (A joint work with V.Kharlamov) We prove that the space of
+affine, transversal at infinity, non-singular real cubic surfaces has 15 connected components. We give a topological criterion to distinguish them and show also how these 15 components are adjacent to each other via wall-crossing.
+----
+  Thursday, June 16, 2022
+:00, room 1-07
+**Prof.  Yakov Eliashberg (Stanford)**
+**“Topology of spaces of Legendrian knots via Algebraic K-theory”**
+Abstract: The highly non-trivial stable homotopy groups of the Waldhausen’s
+h-cobordism space inject into the homotopy groups of spaces of appropriate Legendrian submanifolds. For instance,  there is  a  homotopically non-trivial 2-parametric family of Legendrian unknots in ${\mathbb R}^{2n+1}$ for a sufficiently large $n$. This is a joint work with Thomas Kragh.
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