2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/156342We discuss the problem to develop a mathematical theory of a certain class of nonrational conformal field theories (CFT) which contain the unitary CFT. A variant of the concept of a modular functor is proposed that appears to be suitable for such CFT.44 pagesHigh Energy Physics - TheoryMathematical Physicstext