The Fiedler value λ2, also known as algebraic connectivity, is the second smallest Laplacian eigenvalue of a graph. We study the maximum Fiedler value among all planar graphs G with n vertices, denoted by λ2max, and we show the bounds 2+Θ(1/n2) ≤ λ 2max≤2+O(1/n). We also provide bounds on the maximum Fiedler value for the following classes of planar graphs: Bipartite planar graphs, bipartite planar graphs with minimum vertex-degree 3, and outerplanar graphs. Furthermore, we derive almost tight bounds on λ2max for two more classes of graphs, those of bounded genus and Kh-minor-free graphs. © 2013 Elsevier Inc. All rights reserved.
Barrière, L., Huemer, C., Mitsche, D., & Orden, D. (2013). On the Fiedler value of large planar graphs. Linear Algebra and Its Applications, 439(7), 2070–2084. https://doi.org/10.1016/j.laa.2013.05.032