Quasi-Spectral Characterization of Strongly Distance-Regular Graphs
نویسنده
چکیده
A graph Γ with diameter d is strongly distance-regular if Γ is distanceregular and its distance-d graph Γd is strongly regular. The known examples are all the connected strongly regular graphs (i.e. d = 2), all the antipodal distanceregular graphs, and some distance-regular graphs with diameter d = 3. The main result in this paper is a characterization of these graphs (among regular graphs with d distinct eigenvalues), in terms of the eigenvalues, the sum of the multiplicities corresponding to the eigenvalues with (non-zero) even subindex, and the harmonic mean of the degrees of the distance-d graph. AMS subject classifications. 05C50 05E30
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ورودعنوان ژورنال:
- Electr. J. Comb.
دوره 7 شماره
صفحات -
تاریخ انتشار 2000