A graph H is an absolute retract if for every isometric embedding h of , , into a graph G an edge-preserving map g from G to H exists such that An absolute retract is uniquely determined by its set of embeddable vertices. We may regard this set as a metric space. We also prove that a graph (finite
Absolute retracts of split graphs
✍ Scribed by Sandi Klavžar
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 663 KB
- Volume
- 134
- Category
- Article
- ISSN
- 0012-365X
No coin nor oath required. For personal study only.
✦ Synopsis
It is proved that a split graph is an absolute retract of split graphs if and only if a partition of its vertex set into a stable set and a complete set is unique or it is a complete split graph. Three equivalent conditions for a split graph to be an absolute retract of the class of all graphs are given. It is finally shown that a reflexive split graph G is an absolute retract of reflexive split graphs if and only if G has no retract isomorphic to some J,, n B 3. Here J, is the reflexive graph with vertex set {?c~,x*, . . . , x,,y,, y,, , y,} in which the vertices x1, x2, , x, are mutually adjacent and thevertexy,isadjacent to x~,x~,...,x~_~,x~+~,...,x,.
📜 SIMILAR VOLUMES
A recursive characterization of the absolute retracts in the class of n-chromatic (connected) graphs is given.
A Hamming graph is a Cartesian product of complete graphs. We show that (finite or infinite) quasi-median graphs, which are a generalization of median graphs, are exactly the retracts of Hamming graphs. This generalizes a result of Bandelt (1984,
## Chernyak, A.A. and Z.A. Chernyak, Split dimension of graphs, Discrete Mathematics 89 (1991) l-6.
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