Markus Wappler

Given a connected graph $G=(N,E)$ with node weights $s\in\R^N_+$ and nonnegative edge lengths, we study the following embedding problem related to an eigenvalue optimization problem over the second smallest eigenvalue of the (scaled) Laplacian of $G$: Find $v_i\in\R^{|N|}$, $i\in N$ so that distances between adjacent nodes do not exceed prescribed edge lengths, the weighted barycenter … Read more

We study the problem of maximizing the second smallest eigenvalue of the Laplace matrix of a graph over all nonnegative edge weightings with bounded total weight. The optimal value is the \emph{absolute algebraic connectivity} introduced by Fiedler, who proved tight connections of this value to the connectivity of the graph. Using semidefinite programming techniques and … Read more