2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/213752We study cosmic Nielsen-Olesen strings in space-times with a positive cosmological constant. For the free cosmic string in a cylindrically symmetric space-time, we calculate the contribution of the cosmological constant to the angle deficit, and to the bending of null geodesics. For a cosmic string in a Schwarzschild-de Sitter space-time, we use Kruskal patches around the inner and outer horizons to show that a thin string can pierce them.v3:15pp. References and some explanations added; version accepted for publication in Phys. Rev. DGeneral Relativity and Quantum CosmologyHigh Energy Physics - Theorytext