Number Theory Web Seminar

This number theory seminar is purely online. Our talks come from various corners of the field and of the world. They are streamed live on Zoom.

Organizers:

  • Mike Bennett (University of British Columbia)

  • Philipp Habegger (University of Basel)

  • Alina Ostafe (UNSW Sydney)


There are no fees, but registration is necessary. To register please follow this link.

Registered users will receive an email a few hours before the talk with a link to the Zoom meeting.

Please note the usual dates of the seminar in the FAQ Section. Please also note the varying times in the Tuesday slot, to accommodate more time zones.

Talks are usually 50 minutes and then time for some questions.

News: The Tuesday slots observe a break in the month of August. In September we will continue to have two talks per week.

Contact: ntweb.seminar@gmail.com

Please consider the following:

  • Each talk has a unique Zoom meeting-ID that all registered participants receive by email before the talk. You will receive this email from organizers@ntwebseminar.org. Never publicly share this ID or the password.

  • If you did not received an invitation one hour before the talk please check your spam folder. If you cannot find the email there please contact ntweb.seminar@gmail.com.

  • Some mail servers are blocking our domain. Registered participants can click here to get the link to the next talk.

  • To unsubscribe from the mailing list please follow the link at the bottom of the invitation email.

  • Participant's audio is muted by default. You can unmute to ask questions.

  • You can ask questions in the chat window or by unmuting the microphone and asking them directly.

Next talk:



Özlem Imamoglu, A class number formula of Hurwitz
(ETH Zürich)

Thursday, September 17, 2020 (8am PDT, 11am EDT, 4pm BST, 5pm CEST, 6pm IDT, 8:30pm IST, 11pm China Standard)
Friday, September 18, 2020 (1am AEST, 3am NZST)

Abstract: In a little known paper Hurwitz gave an infinite series representation for the class number of positive definite binary quadratic forms In this talk I will report on joint work with W. Duke and A. Toth where we show how the ideas of Hurwitz can be applied in other settings, in particular to give a formula for the class number of binary cubic forms.


Upcoming talks:

Ilya D. Shkredov, Zaremba's conjecture and growth in groups
(Steklov Mathematical Institute, Moscow)

Tuesday, September 22, 2020 (2am PDT, 5am EDT, 10am BST, 11am CEST, 12pm IDT, 2:30pm IST, 5pm China Standard Time, 7pm AEST, 9pm NZST)

Abstract: Zaremba's conjecture belongs to the area of continued fractions. It predicts that for any given positive integer q there is a positive a, a<q, (a,q)=1 such that all partial quotients b_j in its continued fractions expansion a/q = 1/b_1+1/b_2 +... + 1/b_s are bounded by five. At the moment the question is widely open although the area has a rich history of works by Korobov, Hensley, Niederreiter, Bourgain and many others. We survey certain results concerning this hypothesis and show how growth in groups helps to solve different relaxations of Zaremba's conjecture. In particular, we show that a deeper hypothesis of Hensley concerning some Cantor-type set with the Hausdorff dimension >1/2 takes place for the so-called modular form of Zaremba's conjecture.


Emmanuel Breuillard, A subspace theorem for manifolds
(University of Cambridge)

Thursday, September 24, 2020 (8am PDT, 11am EDT, 4pm BST, 5pm CEST, 6pm IDT, 8:30pm IST, 11pm China Standard Time)
Friday, September 25, 2020 (1am AEST, 3am NZST)

Abstract: In the late 90's Kleinbock and Margulis solved a long-standing conjecture due to Sprindzuk regarding diophantine approximation on submanifolds of R^n. Their method used homogeneous dynamics via the so-called non-divergence estimates for unipotent flows on the space of lattices. In this talk I will explain how these ideas, combined with a certain understanding of the geometry at the heart of Schmidt's subspace theorem, in particular the notion of Harder-Narasimhan filtration, leads to a metric version of the subspace theorem, where the linear forms are allowed to depend on a parameter. This subspace theorem for manifolds allows to quickly compute certain diophantine exponents, and it leads to several generalizations of the Kleinbock-Margulis results in a variety of contexts. Joint work with Nicolas de Saxcé.


Julie Tzu-Yueh Wang, Pisot's d-th root's conjecture for function fields and its complex analog
(Academia Sinica, Taiwan)

Monday, September 28, 2020 (5pm PDT, 8pm EDT)
Tuesday, September 29, 2020 (1am BST, 2am CEST, 3am IDT, 5:30am IST, 8am China Standard Time, 10am AEST, 1pm NZDT)

Abstract: Link to Abstract.


Wei Ho, tba
(University of Michigan)

Thursday, October 1, 2020 (8am PDT, 11am EDT, 4pm BST, 5pm CEST, 6pm IDT, 8:30pm IST, 11pm China Standard Time)
Friday, October 2, 2020 (1am AEST, 4am NZDT)

Abstract: tba


Alexander Smith, tba
(Harvard University)

Monday, October 5, 2020 (5pm PDT, 8pm EDT)
Tuesday, October 6, 2020 (1am BST, 2am CEST, 3am IDT, 5:30am IST, 8am China Standard Time, 11am AEDT, 1pm NZDT)

Abstract: tba


Philippe Michel, tba
(EPFL)

Thursday, October 8, 2020 (8am PDT, 11am EDT, 4pm BST, 5pm CEST, 6pm IDT, 8:30pm IST, 11pm China Standard Time)
Friday, October 9, 2020 (2am AEDT, 4am NZDT)

Abstract: tba


Alexander Gorodnik, tba
(University of Zurich)

Tuesday, October 13, 2020 (2am PDT, 5am EDT, 10am BST, 11am CEST, 12pm IDT, 2:30pm IST, 5pm China Standard Time, 8pm AEDT, 10pm NZDT)

Abstract: tba


Cameron L. Stewart, tba
(University of Waterloo)

Thursday, October 15, 2020 (8am PDT, 11am EDT, 4pm BST, 5pm CEST, 6pm IDT, 8:30pm IST, 11pm China Standard Time)
Friday, October 16, 2020 (2am AEDT, 4am NZDT)

Abstract: tba


Jörg Brüdern, tba
(University of Göttingen)

Tuesday, October 20, 2020 (2am PDT, 5am EDT, 10am BST, 11am CEST, 12pm IDT, 2:30pm IST, 5pm China Standard Time, 8pm AEDT, 10pm NZDT)

Abstract: tba


Sergei Konyagin, tba
(Steklov Institute of Mathematics)

Thursday, October 22, 2020 (8am PDT, 11am EDT, 4pm BST, 5pm CEST, 6pm IDT, 8:30pm IST, 11pm China Standard)
Friday, October 23, 2020 (2am AEDT, 4am NZDT)

Abstract: tba


Gal Binyamini, tba
(Weizmann Institute of Science)

Tuesday, October 27, 2020 (3am PDT, 6am EDT, 10am GMT, 11am CET, 12pm Israel Standard Time, 3:30pm IST, 6pm China Standard Time, 9pm AEDT, 11pm NZDT)

Abstract: tba


Will Sawin, tba
(Columbia University)

Thursday, October 29, 2020 (9am PDT, 12pm EDT, 4pm GMT, 5pm CET, 6pm Israel Standard Time, 9:30pm IST)
Friday, October 30, 2020 (12am China Standard Time, 3am AEDT, 5am NZDT)

Abstract: tba


Pär Kurlberg, tba
(KTH)

Thursday, November 5, 2020 (8am PST, 11am EST, 4pm GMT, 5pm CET, 6pm Israel Standard Time, 9:30pm IST)
Friday, November 6, 2020 (12am China Standard Time, 3am AEDT, 5am NZDT)

Abstract: tba


David Masser, tba
(University of Basel)

Thursday, November 12, 2020 (8am PST, 11am EST, 4pm GMT, 5pm CET, 6pm Israel Standard Time, 9:30pm IST)
Friday, November 13, 2020 (12am China Standard Time, 3am AEDT, 5am NZDT)

Abstract: tba


Chantal David, tba
(Concordia University)

Thursday, November 19, 2020 (8am PST, 11am EST, 4pm GMT, 5pm CET, 6pm Israel Standard Time, 9:30pm IST)
Friday, November 20, 2020 (12am China Standard Time, 3am AEDT, 5am NZDT)

Abstract: tba


Dragos Ghioca, tba
(University of British Columbia)

Monday, November 30, 2020 (5pm PST, 8pm EST)
Tuesday, December 1, 2020 (1am GMT, 2am CET, 3am IST, 6:30am Israel Standard Time, 9am China Standard Time, 12pm AEDT, 2pm NZDT)

Abstract: tba


Rachel Pries, tba
(Colorado State University)

Thursday, December 3, 2020 (8am PST, 11am EST, 4pm GMT, 5pm CET, 6pm Israel Standard Time, 9:30pm IST)
Friday, December 4, 2020 (12am China Standard Time, 3am AEDT, 5am NZDT)

Abstract: tba


Maksym Radziwill, tba
(California Institute of Technology)

Thursday, December 10, 2020 (8am PST, 11am EST, 4pm GMT, 5pm CET, 6pm Israel Standard Time, 9:30pm IST)
Friday, December 11, 2020 (12am China Standard Time, 3am AEDT, 5am NZDT)

Abstract: tba


Sponsors:

We gratefully acknowledge the generous support of:

  • University of Basel (financial support, zoom licence)

  • Max Planck Institute for Mathematics (zoom licence)