You are cordially invited to the Arithmetic Geometry & Number Theory Seminar organized by the Department of Mathematics.
Speaker: Boran Alparslan (Bilkent)
“Almost André in Positive Characteristic”
Abstract: The André–Oort theorem (Jacob Tsimerman together with Pila and Shankar,
2021) characterizes algebraic subvarieties of Shimura varieties that contain a Zariski-dense set of special points: such subvarieties must themselves be special.
In the simplest nontrivial case, Y (1)2C, this classification is particularly explicit. The special curves are the vertical and horizontal fibers above CM points, together with the modular curves defined by the modular polynomials ΦN(X,Y). André’s theorem asserts that any irreducible algebraic curve containing infinitely many special points must belong to this list.
In this talk, I will present a proof of a positive-characteristic variant of André’s theorem for
the product of two modular curves.
Date: Tuesday, November 10, 2026
Time: 14:00-15:00
Place: SA-141 Mathematics Seminar Room