Top-level heading

Alternative Compactifications of M_{g,n} via Cluster Algebras and their Birational Geometry

Categoria
Altro (categoria non censita)
Categoria non censita
Difesa tesi di dottorato
Data e ora inizio evento
Data e ora fine evento
Aula
Aula L
Sede

Dipartimento di Matematica, Sapienza Università di Roma

Speaker
Davide Gori (Sapienza Università di Roma)

We construct new compactifications of $M_{g,n}$ as good moduli spaces of moduli stacks of curves with singularities of type $A_i$ for $i\leq 3$. These are all the partial Q- factorizations of $\overline{M}_{g,n}(7/10)$, the space appearing in the first flip of the Hassett-Keel program, providing a new instance of the modularity principle for the minimal model program of $\overline{M}_{g,n}$. We study the stack of curves with ample log dualizing sheaf and singularities of the above type, establishing a characterization of open substacks that admit a proper good moduli space. We then recover the compactifications via semistability with respect to suitable line bundles on $\overline{\mathcal{M}}_{g,n}(7/10)$, the stack of curves appearing in the first flip of the Hassett-Keel program. Our approach develops a framework for studying semistability with respect to line bundles, revealing a wall-crossing phenomenon in a quotient of the Picard group; in the case of $\overline{\mathcal{M}}_{g,n}(7/10)$, this wall-crossing is given by the cluster fan of certain finite-type cluster algebras. This work extends the results and answers open questions in a paper by Codogni, Tasin, and Viviani.

Contatti/Organizzatori

domenico.fiorenza@uniroma1.it