2018-02-18  16:07 hrs.

### [CANCELADO] Cohomology and equidistribution for higher-rank abelian actions on Heisenberg manifolds, with application to exponential sums.

#### Salvatore CosentinoDepartamento de Matemática e Aplicações, Universidade do Minho, Portugal.

We study the cohomology of the action of an abelian subgroup $P \approx R^d$ of the $(2g+1)$ -dimensional Heisenberg group $H^g$ on the algebra of smooth functions on a homogeneous manifold $\Gamma \backslash H^g$. We show that these actions are cohomologically tamely stable in the sense of Katok, and deduce, using renormalization on an appropriate moduli space (a method used by Flaminio and Forni in the $g=1$ case), a quantitative equidistribution result depending on some diophantine conditions on $P$. As an application, we obtain bounds on certain exponential sums, higher dimensional generalizations of the classical bounds obtained by Hardy and Littlewood for theta sums. This is joint work with Livio Flaminio.

#### Palapa Guillermo Torres -- Jueves 16 de agosto de 2012, 16:30 horas

Unidad Cuernavaca del Instituto de Matemáticas UNAM