We investigate the existence of edge-magic labellings of countably infinite graphs by abelian groups. We show for that for a large class of abelian groups, including the integers ...
Nicholas J. Cavenagh, Diana Combe, Adrian M. Nelso...
We study relational structures (especially graphs and posets) which satisfy the analogue of homogeneity but for homomorphisms rather than isomorphisms. The picture is rather diffe...
We show that the modular decomposition of a countable graph can be defined from this graph, given with an enumeration of its set of vertices, by formulas of Monadic Second-Order l...
Given a universal binary countable homogeneous structure U and n , there is a partition of the induced n-element substructures of U into finitely many classes so that for any par...