Cohomology and equidistribution for higher-rank Abelian actions on Heisenberg manifolds with applications to Theta sums

Room M031
Friday, 9 March, 2018 (All day)

I will present quantitative equidistribution results for the action of Abelian subgroups of the (2g + 1)-dimensional Heisenberg group on a compact homogeneous nilmanifold. The results are based on the study of the cohomology of the action of such groups on the algebra of smooth functions on the nilmanifold, on tame estimates of the associated cohomological equations with respect to a suitable Sobolev grading, and on renormalization in an appropriate moduli space (a method applied by Forni to surface flows and by Forni and Flaminio to other parabolic flows). As an application, we obtain bounds on finite Theta sums defined by real quadratic forms in g variables, depending on certain Diophantine conditions, generalizing to higher dimension the classical bounds by Hardy and Littlewood (1914) and by Fiedler, Jurkat and Korner (1977). This is joint work with Livio Flaminio. 

Speaker: 

Salvatore Cosentino

Institution: 

Universidade do Minho