Algebraic Dynamics Seminar at Harvard
We meet in Room 232 of the Science Center, usually on Thursdays at 4pm. Seminars are typically two hours long, with a break in the middle and the second hour for more details. Please email me (Laura DeMarco) if you are interested in joining the email list, so I can send you announcements. The math department is locked, so you should contact me if you are not from Harvard but would like to attend a lecture.
See also the Informal Geometry & Dynamics seminar on Wednesdays.
Next lecture:
Thursday, October 29, 4-6pm
Ben Church (MIT)
Title: p-adic Siegel disks on K3 surfaces
Abstract: McMullen constructed automorphisms of complex K3 surfaces with positive entropy—and thus chaotic dynamics on a large set—that nonetheless have a Siegel disk: an open region on which the automorphism is holomorphically conjugate to an irrational rotation. Strikingly, such an automorphism forces the K3 surface to be non-projective, so McMullen's examples cannot be written down using explicit equations. Instead they are obtained indirectly via the global Torelli theorem. In this talk we construct a p-adic analogue: a positive cohomological-entropy automorphism with a Siegel disk on a non-projective rigid-analytic K3 surface over a p-adic field. Our construction produces the surface directly using mod p geometry, without access to a Torelli theorem, which gives considerably more flexibility than in the complex case.
Fall 2026
September 10. Michal Szachniewicz, Harvard
September 15 (Tuesday). Snir Ben Ovadia, Hebrew University
October 22. (Special Model Theory seminar) Nate Ackerman
October 29. Ben Church, MIT
November 5. Malavika Mukundan, Boston University
November 12. Ziyang Gao, UCLA
December 2 (Wednesday). Vasiliy Neckrasov, Brandeis University
December 10. Chenxin Huang, Harvard