2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/61010We give a necessary condition for a torus knot to be untied by a single twisting. By using this result, we give infinitely many torus knots that cannot be untied by a single twisting.LaTeX, 12 pages, to appear in Revista Matemática ComplutenseGeometric Topology57M25 (Primary) 57R95 (Secondary)Torus knots that cannot be untied by twistingtext