2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/196863The general solution of the gravitational field equations in the flat Friedmann-Robertson-Walker geometry is obtained in the framework of the full Israel-Stewart-Hiscock theory for a bulk viscous stiff cosmological fluid, with bulk viscosity coefficient proportional to the energy density.7 pages, 6 figuresGeneral Relativity and Quantum Cosmologytext