Brief announcement: Space-time tradeoffs for distributed verification

Mor Baruch, Rafail Ostrovsky, Will Rosenbaum

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


Verifying that a network configuration satisfies a given boolean predicate is a fundamental problem in distributed computing. Many variations of this problem have been studied, for example, in the context of proof labeling schemes (PLS) [12], locally checkable proofs (LCP) [10], and non-deterministic local decision (NLD) [8]. In all of these contexts, verification time is assumed to be constant. Korman, Kutten and Masuzawa [11] presented a proof-labeling scheme for MST, with poly-logarithmic verification time, and logarithmic memory at each vertex. In this paper we introduce the notion of a t-PLS, which allows the verification procedure to run for super-constant time. Our work analyzes the tradeo s of t-PLS between time, label size, message length, and computation space. We construct a universal t-PLS and prove that it uses the same amount of total communication as a known one-round universal PLS, and t factor smaller labels. In addition, we provide a general technique to prove lower bounds for spacetime tradeoffs of t-PLS. We use this technique to show an optimal tradeoff for testing that a network is acyclic (cycle free). Our optimal t-PLS for acyclicity uses label size and computation space O((log n)=t). We further describe a recursive O(log/n) space verifier for acyclicity which does not assume previous knowledge of the run-time t.

Original languageEnglish
Title of host publicationPODC 2016 - Proceedings of the 2016 ACM Symposium on Principles of Distributed Computing
PublisherAssociation for Computing Machinery
Number of pages3
ISBN (Electronic)9781450339643
StatePublished - 25 Jul 2016
Externally publishedYes
Event35th ACM Symposium on Principles of Distributed Computing, PODC 2016 - Chicago, United States
Duration: 25 Jul 201628 Jul 2016

Publication series

NameProceedings of the Annual ACM Symposium on Principles of Distributed Computing


Conference35th ACM Symposium on Principles of Distributed Computing, PODC 2016
Country/TerritoryUnited States


  • Distributed algorithms
  • Proof-labeling schemes
  • Space-time tradeoffs


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