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» On the extension of vertex maps to graph homomorphisms
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67
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DM
2006
82views more  DM 2006»
14 years 10 months ago
On the extension of vertex maps to graph homomorphisms
A reflexive graph is a simple undirected graph where a loop has been added at each vertex. If G and H are reflexive graphs and U V (H), then a vertex map f : U V (G) is called n...
Geir Agnarsson, Li Chen
116
Voted
IPL
2006
153views more  IPL 2006»
14 years 10 months ago
Oriented vertex and arc colorings of outerplanar graphs
A homomorphism from an oriented graph G to an oriented graph H is an arc-preserving mapping from V (G) to V (H), that is (x)(y) is an arc in H whenever xy is an arc in G. The orie...
Alexandre Pinlou, Eric Sopena
101
Voted
ENDM
2007
149views more  ENDM 2007»
14 years 10 months ago
Oriented vertex and arc colorings of partial 2-trees
d Abstract) Pascal Ochem∗, Alexandre Pinlou† LaBRI, Université Bordeaux 1, 351, Cours de la Libération, 33405 Talence Cedex, France March 16, 2007 A homomorphism from an ori...
Pascal Ochem, Alexandre Pinlou
CORR
2006
Springer
128views Education» more  CORR 2006»
14 years 10 months ago
Minimum Cost Homomorphisms to Semicomplete Bipartite Digraphs
For digraphs D and H, a mapping f : V (D)V (H) is a homomorphism of D to H if uv A(D) implies f(u)f(v) A(H). If, moreover, each vertex u V (D) is associated with costs ci(u), i...
Gregory Gutin, Arash Rafiey, Anders Yeo
EJC
2008
14 years 10 months ago
On tension-continuous mappings
Tension-continuous (shortly TT) mappings are mappings between the edge sets of graphs. They generalize graph homomorphisms. From another perspective, tension-continuous mappings a...
Jaroslav Nesetril, Robert Sámal