,
Tianle Jiang
,
Pachara Sawettamalya
,
Huacheng Yu
Creative Commons Attribution 4.0 International license
We revisit several fundamental graph problems in the deterministic two-party communication model. Our main contributions include:
- We give a new Õ(n^{3/2})-bit protocol for computing a maximum matching in general graphs. While the same upper bound can be obtained by simulating the classic algorithms of Micali-Vazirani [Silvio Micali and Vijay V. Vazirani, 1980] and Gabow [Harold N. Gabow, 2017], our protocol is conceptually simple and avoids the intricacies of finding a maximal set of shortest augmenting paths.
- We give a new Õ(n)-bit protocol for negative-cycle detection and negative-weight single-source shortest paths. Our protocol simplifies that of Blikstad et al. [Joakim Blikstad et al., 2022] by replacing a long chain of reductions with a more direct approach based on vertex potentials.
- We give a combinatorial Õ(n)-bit protocol for computing a maximum matching in bipartite graphs, obtained by reinterpreting the near-linear communication protocol of Blikstad et al. [Joakim Blikstad et al., 2022] through a discretized analysis. Together, these results provide simpler protocols for several basic graph problems. We hope they will inspire further advances on the communication complexity of a wide range of graph problems.
@InProceedings{cheng_et_al:LIPIcs.ESA.2026.72,
author = {Cheng, Yu and Jiang, Tianle and Sawettamalya, Pachara and Yu, Huacheng},
title = {{On the Communication Complexity of Maximum Matching and Negative-Weight Shortest Paths}},
booktitle = {34th Annual European Symposium on Algorithms (ESA 2026)},
pages = {72:1--72:22},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-445-1},
ISSN = {1868-8969},
year = {2026},
volume = {388},
editor = {Bille, Philip and Pettie, Seth and Storandt, Sabine},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ESA.2026.72},
URN = {urn:nbn:de:0030-drops-272086},
doi = {10.4230/LIPIcs.ESA.2026.72},
annote = {Keywords: Graph algorithms, communication complexity, maximum matching, negative-weight shortest paths}
}