Periodic automorphisms of surfaces: Invariant circles and maximal orders.
Poincaré automorphisms for nondegenerate CR quadrics.
Polynomial bounds for the number of automorphisms of a surface of general type
Pre-Tango structures and uniruled varieties
The pre-Tango structure is an ample invertible sheaf of locally exact differentials on a variety of positive characteristic. It is well known that pre-Tango structures on curves often induce pathological uniruled surfaces. We show that almost all pre-Tango structures on varieties induce higher-dimensional pathological uniruled varieties, and that each of these uniruled varieties also has a pre-Tango structure. For this purpose, we first consider the p-closed rational vector field induced...