2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/186834We discuss Israel layers collapsing inward from rest at infinity along Schwarzschild-Lemaitre geodesics. The dynamics of the collapsing layer and its equation of state are developed. There is a general equation of state which is approximately polytropic in the limit of very low pressure. The equation of state establishes a new limit on the stress-density ratio.To appear in Phys. Rev. D 15General Relativity and Quantum Cosmologytext