Skip to main content
4 events
when toggle format what by license comment
Dec 1, 2009 at 5:13 comment added Tony Pantev Ah! I see. I misunderstood the question and thought that $\sigma$ can be any automorphism of $A$ as a variety, not as a group.
Dec 1, 2009 at 4:22 comment added Pete L. Clark JSE's comment is well-taken (as is his example). Nevertheless, TP's example was the first one that leapt to my mind as well: the fact that for an (ample, basepoint free) line bundle L on an abelian variety A, the group of translations on A commuting with the corresponding morphism to projective space is the finite group Ker Phi_L: A -> A^{\vee} is of vital importance in the geometry of abelian varieties, e.g. in Mumford's definition of theta groups.
Dec 1, 2009 at 3:50 comment added JSE Regarding this, Tony, there's a notational question of whether translations count for the poster as automorphisms of the abelian variety -- for me, Aut(A) consists of automorphisms of the variety preserving the identity.
Dec 1, 2009 at 3:26 history answered Tony Pantev CC BY-SA 2.5