2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/124628We derive, under a technical assumption, the first variation formula for the eigenvalues of the Laplacian on a closed manifold evolving by the Ricci flow and give some applications.13 pagesDifferential GeometryAnalysis of PDEs53C21; 58J50; 53C44text