Speaker: JongHae Keum (Korea Institute for Advanced Study)
**Time:** 9h30, Friday, December 20, 2019
**Location**: Grand Hall, Building A6, Institute of Mathematics, 18B Hoang Quoc Viet, Cau Giay, Hanoi
**Abstract****:**: These are algebraic surfaces defined over the complex number field with the same Betti numbers as the complex projective plane, and are called $Q$-homology projective planes. I will describe examples and recent progress in the study of such surfaces including the famous smooth examples, the fake projective planes.
The study of these surfaces are related to the study of circle actions of the 5-dimensional sphere in differential topology, which is called the Montgomery-Yang problem.
I will also discuss open questions on this problem |