2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/52145This text collects useful results concerning the quasi-Hopf algebra $\D $. We give a review of issues related to its use in conformal theories and physical mathematics. Existence of such algebras based on 3-cocycles with values in $ {R} / {Z} $ which mimic for finite groups Chern-Simons terms of gauge theories, open wide perspectives in the so called "classification program". The modularisation theorem proved for quasi-Hopf algebras by two authors some years ago makes the computation of topological invariants possible. An updated, although partial, bibliography of recent developments is provided.15 pages, no figureHigh Energy Physics - TheoryRepresentation Theory of Twisted Group Doubletext