Compactifications of $${{\cal M}_{0,n}}$$ Associated with Alexander Self-Dual Complexes: Chow Rings, ψ-Classes, and Intersection Numbers

Abstract

An Alexander self-dual complex gives rise to a compactification of $${{\cal M}_{0,n}}$$ , called an ASD compactification, which is a smooth algebraic variety. ASD compactifications include (but are not exhausted by) the polygon spaces, or the configuration spaces of flexible polygons. We present an explicit description of the Chow rings of ASD compactifications. We study the analogs of Kontsevich’s tautological bundles, compute their Chern classes, compute top intersections of the Chern classes, and derive a recursion for the intersection numbers.