# spectrum

## Are almost all graphs determined by their spectrum? ★★★

Author(s):

**Problem**Are almost all graphs uniquely determined by the spectrum of their adjacency matrix?

Keywords: cospectral; graph invariant; spectrum

## The sum of the two largest eigenvalues ★★

Author(s): Gernert

**Problem**Let be a graph on vertices and let be the eigenvalues of . Is ?

Keywords: eigenvalues; spectrum