The project proposed here is part of basic research of fundamental importance in applied mathematics and theoretical physics and the objective is to contribute to the common solid basis of the above scientific fields provided by the integrable systems. More precisely, we propose to study the mathematical structures underlying integrability of novel families of nonlinear PDEs and difference equations which are associated with the hierarchies of prime solution equations like the KdV equation and are introduced recently by members of the research group at the host institution. The connection of these PDEs with integrable equations describing the gravitational interaction within the context of Einstein's General Relativity is one of the main results of the applicant Ph.D thesis. Taking advantage of this common scientific ground achieved independently by the work of the scientist in charge and the applicant we shall investigate further these novel equations and expand the results within the framework of the ASDYM equations. Using group-theoretical techniques we shall consider the reductions of both families of partial differential and difference equations and elucidate how these powerful techniques which apply to continuous equations may also be applied to their discrete counterparts. The results would clarify how integrable systems arise from above (ASDYM equations) and form below (lattice equations) and-their in-between reductions.