Chromatically optimal rigid graphs
Journal of Combinatorial Theory Series B
Discrete Mathematics - Algebraic graph theory; a volume dedicated to Gert Sabidussi
European Journal of Combinatorics
The complexity of H-colouring of bounded degree graphs
Discrete Mathematics
Homomorphism bounded classes of graphs
European Journal of Combinatorics
Tree-depth, subgraph coloring and homomorphism bounds
European Journal of Combinatorics
Journal of Combinatorial Theory Series B
K5-free bound for the class of planar graphs
European Journal of Combinatorics - Special issue on Eurocomb'03 - graphs and combinatorial structures
Homomorphisms and edge-colourings of planar graphs
Journal of Combinatorial Theory Series B
Grad and classes with bounded expansion III. Restricted graph homomorphism dualities
European Journal of Combinatorics
Bounded-degree forbidden patterns problems are constraint satisfaction problems
CSR'06 Proceedings of the First international computer science conference on Theory and Applications
Universal structures and the logic of forbidden patterns
CSL'06 Proceedings of the 20th international conference on Computer Science Logic
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For every pair of finite connected graphs F and H, and every positive integer k, we construct a universal graph U with the following properties: (1) There is a homomorphism π: U → H, but no homomorphism from F to U. (2) For every graph G with maximum degree no more than k having a homomorphism h:G → H, but no homomorphism from F to G, there is a homomorphism α: G → U, such that h = π o α. Particularly, this solves a problem presented in [1] and [2] regarding the chromatic number of a universal graph.