Chow rings of moduli spaces of genus 0 curves with collisions

Abstract

Introduced in [BB], simplicially stable spaces are alternative compactifications of ${\mathcal{M}}_{g,n}$ generalizing Hassett's moduli spaces of weighted stable curves. We give presentations of the Chow rings of these spaces in genus $0$ using techniques developed by the author in [New25]. When considering the special case of ${\overline{\mathcal{M}}}_{0,n}$, this gives a new proof of Keel's presentation of $\mathrm{CH}({\overline{\mathcal{M}}}_{0,n})$.

17 pages