2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/208284We prove that $n^{7/3}$ is an isoperimetric function for a group of Stallings that is finitely presented but not of type $\mathcal{F}_3$. Note: The authors with Robert Young have now proved a quadratic Dehn function for this group. See arXiv:0712.387715 pages, no figures. Previous bound of $n^{5/2}$ sharpenedGroup Theory20F65text