The Kth largest eigenvalue of a tree

A result related to the largest eigenvalue of a tree

In this note we prove that {0, 1, √ 2, √ 3, 2} is the set of all real numbers ` such that the following holds: every tree having an eigenvalue which is larger than ` has a subtree whose largest eigenvalue is `.

Sharp bound of the kth eigenvalue of trees

The sharp lower bound of the kth largest positive eigenvalue of a tree T with n vertices, and the sharp lower bound of the positive eigenvalues of such a tree Tare worked out in this study. A conjecture on the sharp bound of the kth eigenvalue of such a T is proved.

The largest eigenvalue of nonregular graphs

We give an upper bound for the largest eigenvalue of a nonregular graph with n vertices and the largest vertex degree ∆.

The Largest Eigenvalue Of Sparse Random Graphs

We prove that for all values of the edge probability p(n) the largest eigenvalue of a random graph G(n, p) satisfies almost surely: λ1(G) = (1 + o(1))max{ √ ∆, np}, where ∆ is a maximal degree of G, and the o(1) term tends to zero as max{ √ ∆, np} tends to infinity.

The second largest eigenvalue of trees