Assuming that every proper minor closed class of graphs contains a maximum with respect to the homomorphism order, we prove that such a maximum must be homomorphically equivalent ...
A class of relational structures is said to have the extension preservation property if every first-order sentence that is preserved under extensions on the class is equivalent t...
We show that it is equivalent, for certain sets of finite graphs, to be definable in CMS (counting monadic second-order, a natural extension of monoadic second-order logic), and t...
We extend the work of Letchford (2000) by introducing a new class of valid inequalities for the traveling salesman problem, called the generalized domino-parity (GDP) constraints....
William J. Cook, Daniel G. Espinoza, Marcos Goycoo...
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...