A modular compactification of $\mathcal{M}_{1,n}$ from $A_\infty$-structures

Abstract

We show that a certain moduli space of minimal $A_\infty$-structures coincides with the modular compactification $\bar{\mathcal{M}}_{1,n}(n-1)$ of $\mathcal{M}_{1,n}$ constructed by Smyth. In addition, we describe these moduli spaces and the universal curves over them by explicit equations, prove that they are normal and Gorenstein, show that their Picard groups have no torsion and that they have rational singularities if and only if $n\le 11$.

38 pages, 1 figure; Final version. To appear in Crelle