The Hanna Neumann Conjecture for graphs of free groups with cyclic edge groups

Sam P. Fisher, Ismael Morales

The Hanna Neumann Conjecture (HNC) for a free group $G$ predicts that $\overline{\ddot{I}}‡(U\cap V)\le \overline{\ddot{I}}‡(U)\overline{\ddot{I}}‡(V)$ for all finitely generated subgroups $U$ and $V$, whe…