The homomorphisms of oriented or undirected graphs, the oriented chromatic number, the relationship between acyclic coloring number and oriented chromatic number, have been recently studied. Improving and combining earlier techniques of N.
Mixed graph colorings
β Scribed by Pierre Hansen; Julio Kuplinsky; Dominique de Werra
- Publisher
- Springer
- Year
- 1997
- Tongue
- English
- Weight
- 697 KB
- Volume
- 45
- Category
- Article
- ISSN
- 0340-9422
No coin nor oath required. For personal study only.
π SIMILAR VOLUMES
Suppose /(G)=r and P V(G). It is known that if the distance between any two vertices in P is at least 4, then any (r+1)-coloring of P extends to an (r+1)-coloring of all of G, but an r-coloring of P might not extend to an r-coloring of G. We show that if the distance between any two vertices in P is
Given a property P, graph G. and k 2 0, a P k-coloring is a function 7r: V(G) + { I , ... , k) such that the subgraph induced by each color class has property P; x ( G : P ) is the least k, for which G has a P k-coloring. We investigate here the theory of P colorings. Generalizations of the wellknow
## dedicated to professor w. t. tutte on the occasion of his eightieth birtday It is known that the chromatic number of a graph G=(V, E) with V= [1, 2, ..., n] exceeds k iff the graph polynomial f G => ij # E, i<j (x i &x j ) lies in certain ideals. We describe a short proof of this result, using