A counterexample to Fulton's conjecture on \(\overline M_{0,n}\).
The author gives a counterexample to ``effective'' Fulton's conjecture that any effective divisor on the moduli space \(\overline M_{0,n}\) of \(n\)-pointed rational curves is linearly equivalent to an effective combination of boundary divisors corresponding to singular curves. He constructs effective divisors on \(\overline M_{0,6}\) which are not expressible as above. These examples can be lifted to \(\overline M_{0,n}\) for any \(n\geq 7\).
moduli space of \(n\)-pointed rational curves
scientific article; zbMATH DE number 1749652