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Diophantine properties of nilpotent Lie groups
January 2015 • Menny Aka, Emmanuel Breuillard, Lior Rosenzweig, Nicolas de Saxcé
A finitely generated subgroup ${\rm\Gamma}$ of a real Lie group $G$ is said to be Diophantine if there is ${\it\beta}>0$ such that non-trivial elements in the word ball $B_{{\rm\Gamma}}(n)$ centered at $1\in {\rm\Gamma}$ never approach the identity of $G$ closer than $|B_{{\rm\Gamma}}(n)|^{-{\it\beta}}$ . A Lie group $G$ is said to be Diophantine if for every $k\geqslant 1$ a random $k$ -tuple in $G$ generates a Diophantine subgroup. Semi-simple Lie groups are conjectured to be Diophantine but very little is pr…