Distance-Preserving Subgraphs of Johnson Graphs
Résumé
We give a characterization of distance–preserving subgraphs of Johnson graphs, i.e. of graphs which are isometrically embeddable into Johnson graphs (the Johnson graph J(m, Λ) has the subsets of cardinality m of a set Λ as the vertex–set and two such sets A, B are adjacent iff |A4B| = 2). Our characterization is similar to the characterization of D. ˇZ. Djokovi´c (J. Combin. Th. Ser. B 14 (1973), 263–267) of distance–preserving subgraphs of hypercubes and provides an explicit description of the wallspace (split system) defining the embedding.
Origine : Fichiers produits par l'(les) auteur(s)