2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/140718Two main topics are considered: The characterisation of finite homomorphism dualities for relational structures, and the splitting property of maximal antichains in the homomorphism order.PhD Thesis, 77 pages, 14 figuresCombinatorics18B35; 05C15; 06D20Homomorphisms and Structural Properties of Relational Systemstext