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Dynamics Seminar

Niki-Myrtw MavrakiUniversity of Toronto
Uniform geometry of Post-critically finite special subvarieties.

Thursday, March 27, 2025 - 2:55pm
Malott 206

Many problems in arithmetic geometry have the following form: given a subvariety X of a variety M and a subset Ξ of M, can one describe the structure of the components of the Zariski closure of XΞ? These questions become particularly interesting when the set Ξ has some `special' structure (perhaps related to a group law in M). The expectation is then that the components of ¯XΞ will inherit this structure and be `Ξ-special' themselves. Examples of problems in this form, called `unlikely intersections', include the Manin-Mumford conjecture, the Mordell-Lang conjecture and the Andr\'e-Oort conjecture.

Post Critically finite maps (PCF) are those whose critical points are preperiodic -- they play a special role within the moduli space Md of degree d rational maps. In this talk we will discuss the dynamical Andr\'e-Oort Conjecture (DAO), which asks for a classification of the PCF-special subvarieties in Md. DAO was recently proven in the case of curves by Ji-Xie, following works by many authors, but remains open in higher dimensions. We will discuss results obtained with L. DeMarco and H. Ye, on bounding the geometry of the PCF-special subvarieties. Our results can be thought of as a `uniform DAO'.