Automorphisms of descending mod-p central series

Ricard Riba

Given a free group $\Gamma$ of finite rank $n$ and a prime number $p,$ denote by ${\Gamma }_k^{\bullet }$ the $k^{\text{th}}$ layer of the Stallings ($\bullet =S$) or Zassenhaus ($\bullet =Z$) $p$-cen…