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On pseudo-distance-regularity. (English) Zbl 0978.05050
The author uses (cosines of the) angles between eigenspaces of (the adjacency matrix of) a graph $$G$$ on $$n$$ vertices and the $$i$$th axis of a standard basis of $$\mathbb{R}^n$$ (cf., e.g., the book by the reviewer, P. Rowlinson and S. Simić [Eigenspaces of graphs (Encyclopedia of Mathematics and Its Applications 66. Cambridge: Cambridge University Press) (1997; Zbl 0878.05057)]) and calls them the $$i$$-local multiplicities of the eigenvalues of $$G$$. On this basis, in a previous paper by the author, E. Garriga and J. L. A. Yebra [J. Comb. Theory, Ser. B 68, No. 2, 179-205 (1996; Zbl 0861.05064)] the concept of local pseudo-distance regularity of a graph has been introduced. In the paper under review the author studies some properties of locally distance-regular graphs.

##### MSC:
 05C50 Graphs and linear algebra (matrices, eigenvalues, etc.)
##### Citations:
Zbl 0878.05057; Zbl 0861.05064
Full Text:
##### References:
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