Cohomology bases for the De Concini-Procesi models of hyperplane arrangements and sums over trees

摘要

Let M0.n+1 be the moduli space of N+1-tuples of distinct points on CP1 modulo projective automorphisms. Since a projective automorphism of CP1 is uniquely defined by the images of three points, M0,n+1 can be regarded as the complement in CPn-2 to the projective hyperplane arrangement given by the polynomial z1...zn-1 ∏i