The generalized Mukai conjecture for symmetric varieties

Autor: Gagliardi, Giuliano, Hofscheier, Johannes
Rok vydání: 2014
Předmět:
Zdroj: Trans. Amer. Math. Soc. 369 (2017), 2615-2649
Druh dokumentu: Working Paper
DOI: 10.1090/tran/6738
Popis: We associate to any complete spherical variety $X$ a certain nonnegative rational number $\wp(X)$, which we conjecture to satisfy the inequality $\wp(X) \le \operatorname{dim} X - \operatorname{rank} X$ with equality holding if and only if $X$ is isomorphic to a toric variety. We show that, for spherical varieties, our conjecture implies the generalized Mukai conjecture on the pseudo-index of smooth Fano varieties due to Bonavero, Casagrande, Debarre, and Druel. We also deduce from our conjecture a smoothness criterion for spherical varieties. It follows from the work of Pasquier that our conjecture holds for horospherical varieties. We are able to prove our conjecture for symmetric varieties.
Comment: 33 pages, 2 figures, 6 tables
Databáze: arXiv