Citation Context

...y homomorphism between finite substructures extends to an endomorphism of the structure. It soon turned out that this notion is very relevant in the theory of transformation monoids on countable sets =-=[5, 6, 19, 20, 21]-=-. Moreover, there exists already a rich classification theory for homomorphism-homogeneous structures [2, 7, 11, 12, 16, 17, 18]. Note that by definition, every polymorphism-homogeneous structure is a...