Abstract
The notion of deciding a distributed language \(\mathcal {L} \) is of growing interest in various distributed computing settings. Each process \(p_i\) is given an input value \(x_i\), and the processes should collectively decide whether their set of input values \(x=(x_i)_i\) is a valid state of the system w.r.t. to some specification, i.e., if \(x\in \mathcal {L} \). In non-deterministic distributed decision each process \(p_i\) gets a local certificate \(c_i\) in addition to its input \(x_i\). If the input \(x\in \mathcal {L} \) then there exists a certificate \(c=(c_i)_i\) such that the processes collectively accept x, and if \(x\not \in \mathcal {L} \), then for every c, the processes should collectively reject x. The collective decision is expressed by the set of opinions emitted by the processes.
In this paper we study non-deterministic distributed decision in systems where asynchronous processes may crash. It is known that the number of opinions needed to deterministically decide a language can grow with n, the number of processes in the system. We prove that every distributed language \(\mathcal {L} \) can be non-deterministically decided using only three opinions, with certificates of size \(\lceil \log \alpha (n)\rceil +1\) bits, where \(\alpha \) grows at least as slowly as the inverse of the Ackerman function. The result is optimal, as we show that there are distributed languages that cannot be decided using just two opinions, even with arbitrarily large certificates.
To prove our upper bound, we introduce the notion of distributed encoding of the integers, that provides an explicit construction of a long bad sequence in the well-quasi-ordering \((\{0,1\}^*,\le _*)\) controlled by the successor function. Thus, we provide a new class of applications for well-quasi-orderings that lies outside logic and complexity theory. For the lower bound we use combinatorial topology techniques.
Supported by ECOS-CONACYT Nord grant M12A01, ANR project DISPLEXITY, INRIA project GANG and UNAM-PAPIIT grant.
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Afek, Y., Attiya, H., Dolev, D., Gafni, E., Merritt, M., Shavit, N.: Atomic snapshots of shared memory. J. ACM 40(4), 873–890 (1993)
Attiya, H., Welch, J.: Distributed Computing: Fundamentals, Simulations, and Advanced Topics. Wiley, Chichester (2004)
Bauer, A., Leucker, M., Schallhart, C.: Comparing LTL semantics for runtime verification. J. Log. Comput. 20(3), 651–674 (2010)
Blin, L., Fraigniaud, P., Patt-Shamir, B.: On proof-labeling schemes versus silent self-stabilizing algorithms. In: Felber, P., Garg, V. (eds.) SSS 2014. LNCS, vol. 8756, pp. 18–32. Springer, Heidelberg (2014)
Chandra, T., Toueg, S.: Unreliable failure detectors for reliable distributed systems. J. ACM 43(2), 225–267 (1996)
Cook, B., Podelski, A., Rybalchenko, A.: Proving program termination. Commun. ACM 54(5), 88–98 (2011)
Sarma, A., Holzer, S., Kor, L., Korman, A., Nanongkai, D., Pandurangan, G., Peleg, D., Wattenhofer, R.: Distributed verification and hardness of distributed approximation. SIAM J. Comput. 41(5), 1235–1265 (2012)
Figueira, D., Figueira, S., Schmitz, S., Schnoebelen, P.: Ackermannian and primitive-recursive bounds with dickson’s lemma. In: Proceedings of 26th IEEE Symposium on Logic in Computer Science (LICS), pp. 269–278 (2011)
Fischer, M., Lynch, N., Paterson, M.: Impossibility of distributed consensus with one faulty process. J. ACM 32(2), 374–382 (1985)
Fraigniaud, P., Korman, A., Peleg, D.: Towards a complexity theory for local distributed computing. J. ACM 60(5), 35 (2013)
Fraigniaud, P., Rajsbaum, S., Travers, C.: Locality and checkability in wait-free computing. Distrib. Comput. 26(4), 223–242 (2013)
Fraigniaud, P., Rajsbaum, S., Travers, C.: Minimizing the Number of Opinions for Fault-Tolerant Distributed Decision Using Well-Quasi Orderings Technical report #hal-01237873 (2015). https://hal.archives-ouvertes.fr/hal-01237873v1
Fraigniaud, P., Rajsbaum, S., Travers, C.: On the number of opinions needed for fault-tolerant run-time monitoring in distributed systems. In: Bonakdarpour, B., Smolka, S.A. (eds.) RV 2014. LNCS, vol. 8734, pp. 92–107. Springer, Heidelberg (2014)
Fraigniaud, P., Rajsbaum, S., Roy, M., Travers, C.: The opinion number of set-agreement. In: Aguilera, M.K., Querzoni, L., Shapiro, M. (eds.) OPODIS 2014. LNCS, vol. 8878, pp. 155–170. Springer, Heidelberg (2014)
Göös, M., Suomela, J.: Locally checkable proofs. In: Proceedings of 30th ACM Symposium on Principles of Distributed Computing (PODC), pp. 159–168 (2011)
Haase, C., Schmitz, S., Schnoebelen, P.: The power of priority channel systems. In: D’Argenio, P.R., Melgratti, H. (eds.) CONCUR 2013 – Concurrency Theory. LNCS, vol. 8052, pp. 319–333. Springer, Heidelberg (2013)
Herlihy, M., Kozlov, D., Rajsbaum, S.: Distributed Computing Through Combinatorial Topology. Morgan Kaufmann (2013)
Jeanmougin, M.: Checkability in Asynchronous Error-Prone Distributed Computing Using Few Values. Master Thesis Report, University Paris Diderot (2013)
Korman, A., Kutten, S., Peleg, D.: Proof labeling schemes. Distrib. Comput. 22(4), 215–233 (2010)
Kruskal, J.: The theory of well-quasi-ordering: a frequently discovered concept. J. Comb. Theor. A 13(3), 297–305 (1972)
Milner, E.: Basic WQO- and BQO-theory. In: Rival, I. (ed.) The Role of Graphs in the Theory of Ordered Sets and Its Applications. NATO ASI Series, vol. 147, pp. 487–502. Springer, Netherlands (1985)
Mostafa, M., Bonakdarpour, B.: Decentralized runtime verification of LTL specifications in distributed systems. In: Proceedings of IEEE Parallel and Distributed Processing Symposium (IPDPS), pp. 494–503 (2015)
Schmitz, S., Schnoebelen, P.: Multiply-recursive upper bounds with higman’s lemma. In: Aceto, L., Henzinger, M., Sgall, J. (eds.) ICALP 2011, Part II. LNCS, vol. 6756, pp. 441–452. Springer, Heidelberg (2011)
Schmitz, S., Schnoebelen, P.: Algorithmic Aspects of WQO Theory. Technical report Hal#cel-00727025 (2013). https://cel.archives-ouvertes.fr/cel-00727025v2
Schnoebelen, P.: Verifying lossy channel systems has nonprimitive recursive complexity. Inf. Process. Lett. 83(5), 251–261 (2002)
Schnoebelen, P.: Revisiting ackermann-hardness for lossy counter machines and reset petri nets. In: Hliněný, P., Kučera, A. (eds.) MFCS 2010. LNCS, vol. 6281, pp. 616–628. Springer, Heidelberg (2010)
Turing, A.: Checking a large routine. In: Report of a Conference on High Speed Automatic Calculating Machines, pp. 67–69 (1949)
Acknowledgment
The third author is thankful to Philippe Duchon and Patrick Dehornoy for fruitful discussions on wqos.
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Fraigniaud, P., Rajsbaum, S., Travers, C. (2016). Minimizing the Number of Opinions for Fault-Tolerant Distributed Decision Using Well-Quasi Orderings. In: Kranakis, E., Navarro, G., Chávez, E. (eds) LATIN 2016: Theoretical Informatics. LATIN 2016. Lecture Notes in Computer Science(), vol 9644. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-662-49529-2_37
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