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Main Authors: Li, George Z., Tan, Zihan, Zhang, Tianyi
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2507.09620
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author Li, George Z.
Tan, Zihan
Zhang, Tianyi
author_facet Li, George Z.
Tan, Zihan
Zhang, Tianyi
contents We study vertex sparsification for preserving distances in planar graphs. Given an edge-weighted planar graph with $k$ terminals, the goal is to construct an emulator, which is a smaller edge-weighted planar graph that contains the terminals and exactly preserves the pairwise distances between them. We construct exact planar emulators of size $O(f^2k^2)$ in the setting where terminals lie on $f$ faces in the planar embedding of the input graph. Our result generalizes and interpolates between the previous results of Chang and Ophelders and Goranci, Henzinger, and Peng which is an $O(k^2)$ bound in the setting where all terminals lie on a single face (i.e., $f=1$), and the result of Krauthgamer, Nguyen, and Zondiner, which is an $O(k^4)$ bound for the general case (i.e., $f=k$). Our construction follows a recent new way of analyzing graph structures, by viewing graphs as paths and their intersections, which we believe is of independent interest.
format Preprint
id arxiv_https___arxiv_org_abs_2507_09620
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Paths and Intersections: Exact Emulators for Planar Graphs
Li, George Z.
Tan, Zihan
Zhang, Tianyi
Data Structures and Algorithms
Combinatorics
We study vertex sparsification for preserving distances in planar graphs. Given an edge-weighted planar graph with $k$ terminals, the goal is to construct an emulator, which is a smaller edge-weighted planar graph that contains the terminals and exactly preserves the pairwise distances between them. We construct exact planar emulators of size $O(f^2k^2)$ in the setting where terminals lie on $f$ faces in the planar embedding of the input graph. Our result generalizes and interpolates between the previous results of Chang and Ophelders and Goranci, Henzinger, and Peng which is an $O(k^2)$ bound in the setting where all terminals lie on a single face (i.e., $f=1$), and the result of Krauthgamer, Nguyen, and Zondiner, which is an $O(k^4)$ bound for the general case (i.e., $f=k$). Our construction follows a recent new way of analyzing graph structures, by viewing graphs as paths and their intersections, which we believe is of independent interest.
title Paths and Intersections: Exact Emulators for Planar Graphs
topic Data Structures and Algorithms
Combinatorics
url https://arxiv.org/abs/2507.09620