Adjacency Labelling for Planar Graphs (and Beyond)
Vida Dujmović, Louis Esperet, Cyril Gavoille, Gwenaël Joret, Piotr Micek, Pat Morin
Abstract
We show that there exists an adjacency labelling scheme for planar graphs where each vertex of an n-vertex planar graph G is assigned a (1+o(1))log <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> n-bit label and the labels of two vertices u and v are sufficient to determine if uv is an edge of G. This is optimal up to the lower order term and is the first such asymptotically optimal result. An alternative, but equivalent, interpretation of this result is that, for every positive integer n, there exists a graph Un with n <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1+o(1)</sup> vertices such that every n-vertex planar graph is an induced subgraph of Un. These results generalize to a number of other graph classes, including bounded genus graphs, apex-minor-free graphs, bounded-degree graphs from minor closed families, and k-planar graphs.