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» On recognizing graphs by numbers of homomorphisms
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CORR
2010
Springer
168views Education» more  CORR 2010»
13 years 5 months ago
Upper oriented chromatic number of undirected graphs and oriented colorings of product graphs
The oriented chromatic number of an oriented graph G is the minimum order of an oriented graph H such that G admits a homomorphism to H. The oriented chromatic number of an undire...
Eric Sopena
GC
2010
Springer
13 years 3 months ago
Integer Functions on the Cycle Space and Edges of a Graph
A directed graph has a natural Z-module homomorphism from the underlying graph’s cycle space to Z where the image of an oriented cycle is the number of forward edges minus the n...
Daniel C. Slilaty
IPL
2008
169views more  IPL 2008»
13 years 4 months ago
Oriented colorings of partial 2-trees
A homomorphism from an oriented graph G to an oriented graph H is an arc-preserving mapping f from V(G) to V(H), that is f(x)f(y) is an arc in H whenever xy is an arc in G. The or...
Pascal Ochem, Alexandre Pinlou
IPL
2006
153views more  IPL 2006»
13 years 4 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