“…The interest to the equations from the "negative" flows is to a big extent related to the variety and complexity of their solutions, [38,40,42,43,6,34,31]. Multi-component generalizations of the FL equation have appeared recently in numerous studies like [14,15,29,31,41,50,51,52,53,44] and this naturally leads to the need of their classification from the viewpoint of the simple Lie algebras, the associated symmetric spaces and their reductions. The other multi-component integrable equations in a non-evolutionary form include for example the massive Thirring-like model, whose integrability was shown by Kuznetsov and Mikhailov [37]; its multicomponent extensions were proposed in [48].…”