2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/149472A new proof of a result of Lutz Weis is given, that states that the stability of a positive strongly continuous semigroup $(e^{tA})_{t \ge 0}$ on $L_p$ may be determined by the quantity $s(A)$. We also give an example to show that the dichotomy of the semigroup may not always be determined by the spectrum $σ(A)$.Functional AnalysisPrimary 47D06, Secondary 35B40text