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Linear-size universal point sets for planar graphs

Determine whether there exists a constant c such that, for every n, there is a point set of size c·n that is universal for all n-vertex planar graphs (i.e., supports straight-line crossing-free embeddings of every n-vertex planar graph).

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Background

Universal point sets are central in planar graph drawing. It is known that no universal point set of size n exists for all n-vertex planar graphs, while O(n2) point sets suffice. The current best lower bound is 1.239n−o(n), and the best upper bound is n2/4−O(n).

A linear-size universal point set would significantly advance geometric graph theory and bridge the gap between known lower and upper bounds.

References

Arguably, the most famous open problem in graph drawing, attributed to Bojan Mohar (1988), asks if there exist a constant $c$ such that, for every $n$ there exists a pointset of size $c\cdot n$ that is universal for the class of all $n$-vertex planar graphs.

Free Sets in Planar Graphs: History and Applications (2403.17090 - Dujmović et al., 25 Mar 2024) in Section Applications, Subsection Universal point subsets