הסמינר מתכנס בימי רביעי, בשעות 15:10-16:30, באולם -101

## מפגשים בסמסטר אביב 2018

### המפגשים הבאים

תאריך
כותרת
מרצה
תקציר
21 במרץ תב”ה Leonid Positselski (Higher School of Economics (Moscow))
25 באפר תב”ה Tomer Schlank (Hebrew U. (Jerusalem))
30 במאי תב”ה Ilya Tyomkin (BGU)

### המפגשים הקודמים

תאריך
כותרת
מרצה
תקציר
7 במרץ Equations with singular moduli: effective aspects Yuri Bilu (University of Bordeaux)

A singular modulus is the j-invariant of an elliptic curve with complex multiplication. André (1998) proved that a polynomial equation F(x,y)=0 can have only finitely many solutions in singular moduli (x,y), unless the polynomial F(x,y) is “special” in a certain precisely defined sense. Pila (2011) extended this to equations in many variables, proving the André-Oort conjecture on C^n. The arguments of André and Pila were non-effective (used Siegel-Brauer).

I will report on a recent work by Allombert, Faye, Kühne, Luca, Masser, Pizarro, Riffaut, Zannier and myself about partial effectivization of these results.

14 במרץ Infinite loop spaces in motivic homotopy theory Maria Yakerson (University of Duisburg-Essen (Essen))

Classically in homotopy theory, infinite loop spaces are recognized as spaces with an additional structure: grouplike $E_{\infty}$-spaces. The category of such spaces is equivalent to the category of connective spectra. Replacing topological spaces with smooth schemes, we end up in the realm of motivic homotopy theory, where an analogous statement was sought for since the theory has appeared. In this talk we will discuss the motivic recognition principle, which provides an equivalence between the category of motivic connective spectra and the category of grouplike motivic spaces with so called framed transfers.

This is joint work with Elden Elmanto, Marc Hoyois, Adeel Khan and Vladimir Sosnilo.

סמינר מאורגן על-ידי ד"ר ישי דן-כהן