### Abstract

We consider infrastructure-less highly dynamic networks, where connectivity does not necessarily hold, and the network may actually be disconnected at every time instant. These networks are naturally modeled as time-varying graphs. Clearly the task of designing protocols for these networks is less difficult if the environment allows waiting (i.e., it provides the nodes with store-carry-forward-like mechanisms such as local buffering) than if waiting is not feasible. We provide a quantitative corroboration of this fact in terms of the expressivity of the corresponding time-varying graph; that is in terms of the language generated by the feasible journeys in the graph. We prove that the set of languages L _{nowait} when no waiting is allowed contains all computable languages. On the other end, we prove that L _{wait} is just the family of regular languages. This gap is a measure of the computational power of waiting. We also study bounded waiting; that is when waiting is allowed at a node only for at most d time units. We prove the negative result that L wait[d] = L _{nowait}.

Original language | English |
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Title of host publication | PODC'12 - Proceedings of the 2012 ACM Symposium on Principles of Distributed Computing |

Pages | 99-100 |

Number of pages | 2 |

DOIs | |

Publication status | Published - Aug 20 2012 |

Event | 2012 ACM Symposium on Principles of Distributed Computing, PODC'12 - Madeira, Portugal Duration: Jul 16 2012 → Jul 18 2012 |

### Publication series

Name | Proceedings of the Annual ACM Symposium on Principles of Distributed Computing |
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### Other

Other | 2012 ACM Symposium on Principles of Distributed Computing, PODC'12 |
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Country | Portugal |

City | Madeira |

Period | 7/16/12 → 7/18/12 |

### Fingerprint

### All Science Journal Classification (ASJC) codes

- Software
- Hardware and Architecture
- Computer Networks and Communications

### Cite this

*PODC'12 - Proceedings of the 2012 ACM Symposium on Principles of Distributed Computing*(pp. 99-100). (Proceedings of the Annual ACM Symposium on Principles of Distributed Computing). https://doi.org/10.1145/2332432.2332452

**Brief announcement : Waiting in dynamic networks.** / Casteigts, Arnaud; Flocchini, Paola; Godard, Emmanuel; Santoro, Nicola; Yamashita, Masafumi.

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

*PODC'12 - Proceedings of the 2012 ACM Symposium on Principles of Distributed Computing.*Proceedings of the Annual ACM Symposium on Principles of Distributed Computing, pp. 99-100, 2012 ACM Symposium on Principles of Distributed Computing, PODC'12, Madeira, Portugal, 7/16/12. https://doi.org/10.1145/2332432.2332452

}

TY - GEN

T1 - Brief announcement

T2 - Waiting in dynamic networks

AU - Casteigts, Arnaud

AU - Flocchini, Paola

AU - Godard, Emmanuel

AU - Santoro, Nicola

AU - Yamashita, Masafumi

PY - 2012/8/20

Y1 - 2012/8/20

N2 - We consider infrastructure-less highly dynamic networks, where connectivity does not necessarily hold, and the network may actually be disconnected at every time instant. These networks are naturally modeled as time-varying graphs. Clearly the task of designing protocols for these networks is less difficult if the environment allows waiting (i.e., it provides the nodes with store-carry-forward-like mechanisms such as local buffering) than if waiting is not feasible. We provide a quantitative corroboration of this fact in terms of the expressivity of the corresponding time-varying graph; that is in terms of the language generated by the feasible journeys in the graph. We prove that the set of languages L nowait when no waiting is allowed contains all computable languages. On the other end, we prove that L wait is just the family of regular languages. This gap is a measure of the computational power of waiting. We also study bounded waiting; that is when waiting is allowed at a node only for at most d time units. We prove the negative result that L wait[d] = L nowait.

AB - We consider infrastructure-less highly dynamic networks, where connectivity does not necessarily hold, and the network may actually be disconnected at every time instant. These networks are naturally modeled as time-varying graphs. Clearly the task of designing protocols for these networks is less difficult if the environment allows waiting (i.e., it provides the nodes with store-carry-forward-like mechanisms such as local buffering) than if waiting is not feasible. We provide a quantitative corroboration of this fact in terms of the expressivity of the corresponding time-varying graph; that is in terms of the language generated by the feasible journeys in the graph. We prove that the set of languages L nowait when no waiting is allowed contains all computable languages. On the other end, we prove that L wait is just the family of regular languages. This gap is a measure of the computational power of waiting. We also study bounded waiting; that is when waiting is allowed at a node only for at most d time units. We prove the negative result that L wait[d] = L nowait.

UR - http://www.scopus.com/inward/record.url?scp=84864973692&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84864973692&partnerID=8YFLogxK

U2 - 10.1145/2332432.2332452

DO - 10.1145/2332432.2332452

M3 - Conference contribution

AN - SCOPUS:84864973692

SN - 9781450314503

T3 - Proceedings of the Annual ACM Symposium on Principles of Distributed Computing

SP - 99

EP - 100

BT - PODC'12 - Proceedings of the 2012 ACM Symposium on Principles of Distributed Computing

ER -