S000393


Eigenvalues of the adjacency matrix for the 10-node Petersen graph.

-2, -2, -2, -2, 1, 1, 1, 1, 1, 3

1

S000393

There are 30240 adjacency matrices for this graph, but they all have the same set of eigenvalues.

T. D. Noe, Plot of 10 terms

Eric W. Weisstein, MathWorld: Petersen Graph

(Mma) t = Table[0, {10}, {10}]; con = {{2, 5, 6}, {1, 3, 7}, {2, 4, 8}, {3, 5, 9}, {1, 4, 10}, {1, 8, 9}, {2, 9, 10}, {3, 6, 10}, {4, 6, 7}, {5, 7, 8}}; Do[t[[i, con[[i]]]] = t[[con[[i]], i]] = 1, {i, 10}]; Sort[Eigenvalues[t]]

Cf. S000392.

nonn,full

T. D. Noe, Dec 08 2014

© Tony D Noe 2014-2015