4. Miscellaneous
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Growths functions of repetitive graphs
A graph $\Gamma$ is called repetitive if for all $r > 0$ there exists $d > 0$ such that for all $x,y \in \Gamma$, there exists an isomorphic copy of $B_r(x)$ (the ball of radius $r$ centered at $x$) at distance less or equal to $d$ from $y$. \\
Consider two kind of growths functions for $\Gamma$: pick $x_0 \in \Gamma$ and define $f_{x_0}(n) = \# B_n(x_0)$ and $f(x) = \max \left\{f_x(n): x \in \Gamma\right\}$Problem 4.1.
[Nicolas Matte Bon] What functions can be realized as growths functions of repetitive graphs? -
Nekrashevych C*-algebras
Problem 4.2.
When is the Nekrashevych $C^*$-algebra of a contracting group simple?
Cite this as: AimPL: Groups of dynamical origin, available at http://aimpl.org/groupdynamorigin.