Shokurov's conjecture on conic bundles with canonical singularities
Speaker: Prof. Jingjun Han (John Hopkins)

Time: 8h00, Friday, August 27, 2021

Zoom Meeting


Meeting ID: 827 7229 2046

Passcode: 830392

Abstract: A conic bundle is a contraction $Xto Z$ between normal varieties of relative dimension $1$ such that the anit-canonical divisor is relatively ample. In this talk, I will prove a conjecture of Shokurov which predicts that, if $Xto Z$ is a conic bundle such that $X$ has canonical singularities, then base variety $Z$ is always $frac{1}{2}$-lc, and the multiplicities of the fibers over codimension $1$ points are bounded from above by $2$. Both values $frac{1}{2}$ and $2$ are sharp. This is a joint work with Chen Jiang and Yujie Luo.