Randomized and Quantum Query Complexities of Finding a King in a Tournament

Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review

Documents

  • Fulltext

    Final published version, 814 KB, PDF document

A tournament is a complete directed graph. It is well known that every tournament contains at least one vertex v such that every other vertex is reachable from v by a path of length at most 2. All such vertices v are called kings of the underlying tournament. Despite active recent research in the area, the best-known upper and lower bounds on the deterministic query complexity (with query access to directions of edges) of finding a king in a tournament on n vertices are from over 20 years ago, and the bounds do not match: the best-known lower bound is O(n4/3) and the best-known upper bound is O(n3/2) [Shen, Sheng, Wu, SICOMP'03]. Our contribution is to show tight bounds (up to logarithmic factors) of eT(n) and eT(v n) in the randomized and quantum query models, respectively. We also study the randomized and quantum query complexities of finding a maximum out-degree vertex in a tournament.

Original languageEnglish
Title of host publication43rd IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science, FSTTCS 2023
EditorsPatricia Bouyer, Srikanth Srinivasan, Srikanth Srinivasan
Number of pages19
PublisherSchloss Dagstuhl- Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing
Publication date2023
Article number30
ISBN (Electronic)9783959773041
DOIs
Publication statusPublished - 2023
Event43rd IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science, FSTTCS 2023 - Hyderabad, India
Duration: 18 Dec 202320 Dec 2023

Conference

Conference43rd IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science, FSTTCS 2023
LandIndia
ByHyderabad
Periode18/12/202320/12/2023
SeriesLeibniz International Proceedings in Informatics, LIPIcs
Volume284
ISSN1868-8969

Bibliographical note

Publisher Copyright:
© 2023 Schloss Dagstuhl- Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing. All rights reserved.

    Research areas

  • quantum computing, Query complexity, randomized query complexity, search problems, tournament solutions

ID: 390880146