,
Vida Dujmović
,
Hussein Houdrouge
,
Pat Morin
,
Saeed Odak
Creative Commons Attribution 4.0 International license
A dominating set of a graph G is connected if it induces a connected graph in G. For planar triangulations, it has been known since 1990 that every n-vertex triangulation admits a connected dominating set of size at most n/2 - 1, and no improvement to this bound was known for over three decades. We break this longstanding barrier by showing that every n-vertex triangulation has a connected dominating set of size at most 10n/21. Equivalently, every triangulation admits a spanning tree with at least 11n/21 leaves. Moreover, we present an algorithm that computes such a set in optimal linear time. Our result narrows the gap to the best known lower bound and has graph drawing applications, establishing a bound for one-bend free sets and improving the known bound for simultaneous planar embeddings.
@InProceedings{bose_et_al:LIPIcs.ICALP.2026.41,
author = {Bose, Prosenjit and Dujmovi\'{c}, Vida and Houdrouge, Hussein and Morin, Pat and Odak, Saeed},
title = {{Connected Dominating Sets in Triangulations}},
booktitle = {53rd International Colloquium on Automata, Languages, and Programming (ICALP 2026)},
pages = {41:1--41:21},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-428-4},
ISSN = {1868-8969},
year = {2026},
volume = {374},
editor = {Bhattacharya, Sayan and Nanongkai, Danupon and Benedikt, Michael and Puppis, Gabriele},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ICALP.2026.41},
URN = {urn:nbn:de:0030-drops-264300},
doi = {10.4230/LIPIcs.ICALP.2026.41},
annote = {Keywords: connected domination, triangulations, planar graphs, graph drawing, collinear sets}
}