2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/58924We develop a theory of non-unitary set-theoretical solutions to the Quantum Yang-Baxter equation. Our results generalize those obtained by Etingof, Schedler and the author. We remark that some of our constructions are similar to constructions obtained by Lu, Yan and Zhu.AMS-LaTeX v1.2, 19 pages, no figures, corrected small mistakes in the proofs of Lemma 3 and Theorem 2.8Quantum Algebratext