On the commensurator of the Nottingham group
On the commensurator of the Nottingham group
Let $p\geq 5$ be a prime number. We prove that the abstract commensurator of the Nottingham group $\mathcal {N}(\mathbb {F}_p)$ coincides with its automorphism group, which is known to be a finite extension of $\mathcal {N}(\mathbb {F}_p)$. As a corollary we deduce that the Nottingham group cannot be embedded as …