License: Creative Commons Attribution 4.0 International license (CC BY 4.0)
When quoting this document, please refer to the following
DOI: 10.4230/LIPIcs.STACS.2022.16
URN: urn:nbn:de:0030-drops-158262
URL: http://dagstuhl.sunsite.rwth-aachen.de/volltexte/2022/15826/
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Bouyer, Patricia ; Randour, Mickael ; Vandenhove, Pierre

Characterizing Omega-Regularity Through Finite-Memory Determinacy of Games on Infinite Graphs

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LIPIcs-STACS-2022-16.pdf (0.8 MB)

Abstract

We consider zero-sum games on infinite graphs, with objectives specified as sets of infinite words over some alphabet of colors. A well-studied class of objectives is the one of ω-regular objectives, due to its relation to many natural problems in theoretical computer science. We focus on the strategy complexity question: given an objective, how much memory does each player require to play as well as possible? A classical result is that finite-memory strategies suffice for both players when the objective is ω-regular. We show a reciprocal of that statement: when both players can play optimally with a chromatic finite-memory structure (i.e., whose updates can only observe colors) in all infinite game graphs, then the objective must be ω-regular. This provides a game-theoretic characterization of ω-regular objectives, and this characterization can help in obtaining memory bounds. Moreover, a by-product of our characterization is a new one-to-two-player lift: to show that chromatic finite-memory structures suffice to play optimally in two-player games on infinite graphs, it suffices to show it in the simpler case of one-player games on infinite graphs. We illustrate our results with the family of discounted-sum objectives, for which ω-regularity depends on the value of some parameters.

BibTeX - Entry

@InProceedings{bouyer_et_al:LIPIcs.STACS.2022.16,
  author =	{Bouyer, Patricia and Randour, Mickael and Vandenhove, Pierre},
  title =	{{Characterizing Omega-Regularity Through Finite-Memory Determinacy of Games on Infinite Graphs}},
  booktitle =	{39th International Symposium on Theoretical Aspects of Computer Science (STACS 2022)},
  pages =	{16:1--16:16},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-222-8},
  ISSN =	{1868-8969},
  year =	{2022},
  volume =	{219},
  editor =	{Berenbrink, Petra and Monmege, Benjamin},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/opus/volltexte/2022/15826},
  URN =		{urn:nbn:de:0030-drops-158262},
  doi =		{10.4230/LIPIcs.STACS.2022.16},
  annote =	{Keywords: two-player games on graphs, infinite arenas, finite-memory determinacy, optimal strategies, \omega-regular languages}
}

Keywords: two-player games on graphs, infinite arenas, finite-memory determinacy, optimal strategies, ω-regular languages
Collection: 39th International Symposium on Theoretical Aspects of Computer Science (STACS 2022)
Issue Date: 2022
Date of publication: 09.03.2022

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