2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/34885If the cosmological constant $Λ$ can not be neglected, we will show in this short report, that graviton should have a rest mass $m_g=\sqrt{2Λ}=\sqrt{2Λ}\hbar c^{-1}$ different from zero.General Relativity and Quantum Cosmologytext