Equations of $\,\overline{{M}}_{0,n}$

Abstract

Following work of Keel and Tevelev, we give explicit polynomials in the Cox ring of $\mathbb{P}^1\times\cdots\times\mathbb{P}^{n-3}$ that, conjecturally, determine $\overline{M}_{0,n}$ as a subscheme. Using Macaulay2, we prove that these equations generate the ideal for $n=5, 6, 7, 8$. For $n \leq 6$ we give a cohomological proof that these polynomials realize $\overline{M}_{0,n}$ as a projective variety, embedded in $\mathbb{P}^{(n-2)!-1}$ by the complete log canonical linear system.