{"year":"2023","language":[{"iso":"eng"}],"external_id":{"arxiv":["2211.10151"]},"publication_identifier":{"isbn":["9783959772631"],"issn":["1868-8969"]},"file":[{"success":1,"creator":"cchlebak","date_updated":"2026-07-22T08:04:03Z","date_created":"2026-07-22T08:04:03Z","file_size":1077427,"content_type":"application/pdf","access_level":"open_access","file_name":"2023_LIPIcs_El-Hayek.pdf","file_id":"22383","relation":"main_file","checksum":"d7f45fdcbc5fccd61db69f56d775c636"}],"editor":[{"last_name":"Tauman Kalai","full_name":"Tauman Kalai, Yael","first_name":"Yael"}],"publication":"14th Innovations in Theoretical Computer Science Conference","publication_status":"published","acknowledgement":" This project has received funding from the European Research Council (ERC) under\r\nthe European Union’s Horizon 2020 research and innovation programme (grant agreement No.\r\n101019564). This work was further supported by the Austrian Science Fund (FWF) and netIDEE\r\nSCIENCE project P 33775-N, as well as the FWF project I 4800-N (ADVISE)","abstract":[{"text":"Data dissemination is a fundamental task in distributed computing. This paper studies broadcast problems in various innovative models where the communication network connecting n processes is dynamic (e.g., due to mobility or failures) and controlled by an adversary. \r\nIn the first model, the processes transitively communicate their ids in synchronous rounds along a rooted tree given in each round by the adversary whose goal is to maximize the number of rounds until at least one id is known by all processes. Previous research has shown a ⌈(3n-1)/2⌉-2 lower bound and an O(nlog log n) upper bound. We show the first linear upper bound for this problem, namely ⌈(1+√2) n-1⌉ ≈ 2.4n.\r\nWe extend these results to the setting where the adversary gives in each round k-disjoint forests and their goal is to maximize the number of rounds until there is a set of k ids such that each process knows of at least one of them. We give a ⌈3(n-k)/2⌉-1 lower bound and a (π²+6)/6 n+1 ≈ 2.6n upper bound for this problem.\r\nFinally, we study the setting where the adversary gives in each round a directed graph with k roots and their goal is to maximize the number of rounds until there exist k ids that are known by all processes. We give a ⌈3(n-3k)/2⌉+2 lower bound and a ⌈(1+√2)n⌉+k-1 ≈ 2.4n+k upper bound for this problem.\r\nFor the two latter problems no upper or lower bounds were previously known.","lang":"eng"}],"title":"Asymptotically tight bounds on the time complexity of broadcast and its variants in dynamic networks","extern":"1","day":"01","ddc":["000"],"author":[{"last_name":"El-Hayek","id":"888a098e-fcac-11ee-aff7-d347be57b725","orcid":"0000-0003-4268-7368","full_name":"El-Hayek, Antoine","first_name":"Antoine"},{"full_name":"Henzinger, Monika H","first_name":"Monika H","orcid":"0000-0002-5008-6530","last_name":"Henzinger","id":"540c9bbd-f2de-11ec-812d-d04a5be85630"},{"orcid":"0000-0002-7798-1711","last_name":"Schmid","full_name":"Schmid, Stefan","first_name":"Stefan"}],"oa":1,"article_processing_charge":"No","status":"public","alternative_title":["LIPIcs"],"arxiv":1,"article_number":"47","citation":{"apa":"El-Hayek, A., Henzinger, M., &#38; Schmid, S. (2023). Asymptotically tight bounds on the time complexity of broadcast and its variants in dynamic networks. In Y. Tauman Kalai (Ed.), <i>14th Innovations in Theoretical Computer Science Conference</i> (Vol. 251). Cambridge, Massachusetts, USA: Schloss Dagstuhl - Leibniz-Zentrum für Informatik. <a href=\"https://doi.org/10.4230/LIPICS.ITCS.2023.47\">https://doi.org/10.4230/LIPICS.ITCS.2023.47</a>","ieee":"A. El-Hayek, M. Henzinger, and S. Schmid, “Asymptotically tight bounds on the time complexity of broadcast and its variants in dynamic networks,” in <i>14th Innovations in Theoretical Computer Science Conference</i>, Cambridge, Massachusetts, USA, 2023, vol. 251.","ama":"El-Hayek A, Henzinger M, Schmid S. Asymptotically tight bounds on the time complexity of broadcast and its variants in dynamic networks. In: Tauman Kalai Y, ed. <i>14th Innovations in Theoretical Computer Science Conference</i>. Vol 251. Schloss Dagstuhl - Leibniz-Zentrum für Informatik; 2023. doi:<a href=\"https://doi.org/10.4230/LIPICS.ITCS.2023.47\">10.4230/LIPICS.ITCS.2023.47</a>","mla":"El-Hayek, Antoine, et al. “Asymptotically Tight Bounds on the Time Complexity of Broadcast and Its Variants in Dynamic Networks.” <i>14th Innovations in Theoretical Computer Science Conference</i>, edited by Yael Tauman Kalai, vol. 251, 47, Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2023, doi:<a href=\"https://doi.org/10.4230/LIPICS.ITCS.2023.47\">10.4230/LIPICS.ITCS.2023.47</a>.","short":"A. El-Hayek, M. Henzinger, S. Schmid, in:, Y. Tauman Kalai (Ed.), 14th Innovations in Theoretical Computer Science Conference, Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2023.","chicago":"El-Hayek, Antoine, Monika Henzinger, and Stefan Schmid. “Asymptotically Tight Bounds on the Time Complexity of Broadcast and Its Variants in Dynamic Networks.” In <i>14th Innovations in Theoretical Computer Science Conference</i>, edited by Yael Tauman Kalai, Vol. 251. Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2023. <a href=\"https://doi.org/10.4230/LIPICS.ITCS.2023.47\">https://doi.org/10.4230/LIPICS.ITCS.2023.47</a>.","ista":"El-Hayek A, Henzinger M, Schmid S. 2023. Asymptotically tight bounds on the time complexity of broadcast and its variants in dynamic networks. 14th Innovations in Theoretical Computer Science Conference. ITCS: Innovations in Theoretical Computer Science, LIPIcs, vol. 251, 47."},"date_published":"2023-02-01T00:00:00Z","user_id":"8b945eb4-e2f2-11eb-945a-df72226e66a9","intvolume":"       251","publisher":"Schloss Dagstuhl - Leibniz-Zentrum für Informatik","file_date_updated":"2026-07-22T08:04:03Z","doi":"10.4230/LIPICS.ITCS.2023.47","quality_controlled":"1","date_updated":"2026-07-24T12:48:29Z","volume":251,"date_created":"2026-07-20T11:45:04Z","month":"02","_id":"22373","oa_version":"Published Version","scopus_import":"1","related_material":{"record":[{"status":"public","relation":"dissertation_contains","id":"22281"}]},"keyword":["broadcast","cover","k-broadcast","dynamic radius","dynamic graphs","oblivious message adversary","time complexity","Theory of computation → Distributed algorithms","Networks → Network algorithms"],"tmp":{"image":"/images/cc_by.png","short":"CC BY (4.0)","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode"},"has_accepted_license":"1","conference":{"start_date":"2023-01-10","end_date":"2023-01-13","location":"Cambridge, Massachusetts, USA","name":"ITCS: Innovations in Theoretical Computer Science"},"type":"conference"}