2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/220923We prove that for some knot-like objects one can easily recognize non-equivalence w.r.t. all Reidemeister moves by studying some equivalence classes modulo only 2nd Reidemeister moves. There are applications to virtual knots, graph-links and looped graphs.13 pages, 11 FiguresGeometric TopologyCombinatorics57M25text