99 search results - page 6 / 20 » On a class of finite symmetric graphs |
DM
2006
13 years 8 months ago
2006
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 ...
ICALP
2005
Springer
14 years 1 months ago
2005
Springer
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...
CORR
2006
Springer
13 years 8 months ago
2006
Springer
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...
MOR
2010
13 years 6 months ago
2010
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....
COMBINATORICS
2006
13 years 8 months ago
2006
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 ...