Tue, September 16, 2014
3:00 pm - 4:00 pm
MW 154
Title: A Semi-Ampleness Criterion for Divisors on the Moduli Space of Stable Pointed Rational Curves
Speaker: Maksym Fedorchuk, Boston College
Abstract: We develop a new combinatorial approach to proving base point freeness of divisors on $\overline{M}_{0,n}$. On one hand, this leads to a simple sufficient criterion for an S_n-symmetric divisor to be semi-ample. On the other hand, we construct infinite series of semi-ample divisors associated to cyclic quadratic forms satisfying certain positivity properties.