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Expansion of gap-planar graphs

Published: September 3, 2025 | arXiv ID: 2509.03121v1

By: David R. Wood

Potential Business Impact:

Makes drawings of tricky maps with fewer crossing lines.

Business Areas:
Parks Travel and Tourism

A graph is $k$-gap-planar if it has a drawing in the plane such that every crossing can be charged to one of the two edges involved so that at most $k$ crossings are charged to each edge. We show this class of graphs has linear expansion. In particular, every $r$-shallow minor of a $k$-gap-planar graph has density $O(rk)$. Several extensions of this result are proved: for topological minors, for $k$-cover-planar graphs, for $k$-gap-cover-planar graphs, and for drawings on any surface. Application to graph colouring are presented.

Country of Origin
🇦🇺 Australia

Page Count
16 pages

Category
Mathematics:
Combinatorics