A pleasant surprise of the cyclotomic character

Seminar
Algebra
Speaker
Vasily Dolgushev (Temple University)
Date
18/12/2024 - 17:00 - 16:00Add to Calendar 2024-12-18 16:00:00 2024-12-18 17:00:00 A pleasant surprise of the cyclotomic character In 1990, V. Drinfeld introduced the Grothendieck-Teichmueller group GT. This group receives a homomorphism from the absolute Galois group G_Q of rational numbers, and this homomorphism is injective due to Belyi's theorem.  In his 1990 ICM talk, Y. Ihara posed a very hard question about the surjectivity of this homomorphism from G_Q to GT.   In my talk, I will introduce the groupoid of GT-shadows and show how this groupoid is related to the group GT. I will formulate a version of Ihara's question for GT-shadows and describe a family of objects of the groupoid for which this question has a positive answer. My talk is based on the joint paper https://arxiv.org/abs/2405.11725 with I. Bortnovskyi, B. Holikov and V. Pashkovskyi.   ================================================ https://us02web.zoom.us/j/87856132062   Meeting ID: 878 5613 2062 Zoom only -- see link below אוניברסיטת בר-אילן - Department of Mathematics mathoffice@math.biu.ac.il Asia/Jerusalem public
Place
Zoom only -- see link below
Abstract

In 1990, V. Drinfeld introduced the Grothendieck-Teichmueller group GT. This group receives a

homomorphism from the absolute Galois group G_Q of rational numbers, and this homomorphism is injective due to Belyi's theorem.  In his 1990 ICM talk, Y. Ihara posed a very hard question about the surjectivity of this homomorphism from G_Q to GT.

 

In my talk, I will introduce the groupoid of GT-shadows and show how this groupoid is related to the group GT. I will formulate a version of Ihara's question for GT-shadows and describe a family of objects of the groupoid for which this question has a positive answer. My talk is based on the joint paper https://arxiv.org/abs/2405.11725 with I. Bortnovskyi, B. Holikov and V. Pashkovskyi.

 

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https://us02web.zoom.us/j/87856132062

 

Meeting ID: 878 5613 2062

Last Updated Date : 04/12/2024