Hyperplane Arrangement Seminar Derivations of an effective divisor on the complex projective line IV
 Date

20061101 13:00 
20061101 14:30
 Place
 Room 8302, Faculty of Science Bldg. #8, Hokkaido University

Speaker/Organizer
 Max Wakefield (Hokkaido University)

 In this talk we consider an effective divisor on the complex projective lineand associate with it the module D consisting of all the derivations $\theta$such that $\theta(I_i)\subset I_i^{m_i}$ for every $i$, where $I_i$ is theideal of $p_i$.The module D is graded and free of rank 2;the degrees of its homogeneous basis, called the exponents, form an importantinvariant of the divisor. Our main result asserts that under some conditionsfor $(m_i)$ there exists a general position of $n$ points for which theexponents do not change. We give an explicit formula for them.This talk is the fourth in a series of talks whose aim it is to prove ourmain result.
http://coe.math.sci.hokudai.ac.jp/sympo/arrangement/index_en.html