A simple proof of a theorem of Karrass and Solitar

2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/73096In this note we give a particularly short and simple proof of the following theorem of Karrass and Solitar. Let $H$ be a finitely generated subgroup of a free group $F$ with infinite index $[F:H]$. Then there is a nontrivial normal subgroup $N$ of $F$ such that $N\cap H = \{1\}$.2 pages. to appearGroup Theory20E05A simple proof of a theorem of Karrass and Solitartext