2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/65446We give a cellular decomposition of the compact connected Lie group $Spin(7)$. We also determine the L-S categories of $Spin(7)$ and $Spin(8)$.14 pagesAlgebraic TopologyGroup Theory55M30; 22E20, 57N60On the cellular decomposition and the Lusternik-Schnirelmann category of $Spin(7)$text