Applications of the Subspace Theorem in Group Theory
Applications of the Subspace Theorem in Group Theory
In-Person and Online Talk
Zoom Link: https://theias.zoom.us/j/88393312988?pwd=emtLbTJ5ZnMvS3hBVmNmYjhIUEFIdz09(link is external)
An abstract group is said to have the {\it bounded generation} property (BG) if it can be written as a product of finitely many cyclic subgroups. Being a purely combinatorial notion, bounded generation has close relation with many group theoretical problems including semisimple rigidity, Kazhdan's property (T) and Serre's congruence subgroup problem.
In this talk, I will explain how to use the Schlickewei-Schmidt subspace theorem in Diophantine approximation to prove that the distribution of the points of a set of matrices over a number field F with (BG) by certain fixed semi-simple (diagonalizable) elements is of at most logarithmic size when ordered by height. Moreover, one obtains that a linear group Γ⊂GLn(K) over a field K of characteristic zero admits a {\it purely exponential parametrization} if and only if it is finitely generated and the connected component of its Zariski closure is a torus.
This is joint work with Corvaja, Demeio, Rapinchuk and Zannier.