The Experts below are selected from a list of 210 Experts worldwide ranked by ideXlab platform

Nayuta Yanagisawa - One of the best experts on this subject based on the ideXlab platform.

  • SIROCCO - A Characterization of t-Resilient Colorless Task Anonymous Solvability
    Structural Information and Communication Complexity, 2018
    Co-Authors: Carole Delporte-gallet, Hugues Fauconnier, Sergio Rajsbaum, Nayuta Yanagisawa
    Abstract:

    One of the central questions in distributed computability is characterizing the Tasks that are solvable in a given system model. In the anonymous case, where processes have no identifiers and communicate through multi-writer/multi-reader registers, there is a recent topological characterization (Yanagisawa 2017) of the Colorless Tasks that are solvable when any number of asynchronous processes may crash. In this paper, we consider the case where at most t asynchronous processes may crash, where \(1\le t

  • A Characterization of t-Resilient Colorless Task Anonymous Solvability
    2018
    Co-Authors: Carole Delporte-gallet, Hugues Fauconnier, Sergio Rajsbaum, Nayuta Yanagisawa
    Abstract:

    One of the central questions in distributed computability is characterizing the Tasks that are solvable in a given system model. In the anonymous case, where processes have no identifiers and communicate through multi-writer/multi-reader registers, there is a recent topologi-cal characterization (Yanagisawa 2017) of the Colorless Tasks that are solvable when any number of asynchronous processes may crash. In this paper, we consider the case where at most t asynchronous processes may crash, where 1 ≤ t < n. We prove that a Colorless Task is t-resilient solvable anonymously if and only if it is t-resilient solvable non-anonymously. We obtain our results through various reductions and simulations that explore how to extend techniques for non-anonymous computation to anonymous one.

  • a characterization of t resilient Colorless Task anonymous solvability
    SIROCCO 2018 - 25th International Colloquium Structural Information and Communication Complexity, 2018
    Co-Authors: Carole Delportegallet, Hugues Fauconnier, Sergio Rajsbaum, Nayuta Yanagisawa
    Abstract:

    One of the central questions in distributed computability is characterizing the Tasks that are solvable in a given system model. In the anonymous case, where processes have no identifiers and communicate through multi-writer/multi-reader registers, there is a recent topological characterization (Yanagisawa 2017) of the Colorless Tasks that are solvable when any number of asynchronous processes may crash. In this paper, we consider the case where at most t asynchronous processes may crash, where \(1\le tColorless Task is t-resilient solvable anonymously if and only if it is t-resilient solvable non-anonymously. We obtain our results through various reductions and simulations that explore how to extend techniques for non-anonymous computation to anonymous one.

  • A characterization of Colorless anonymous t-resilient Task computability.
    arXiv: Distributed Parallel and Cluster Computing, 2017
    Co-Authors: Carole Delporte-gallet, Hugues Fauconnier, Sergio Rajsbaum, Nayuta Yanagisawa
    Abstract:

    A Task is a distributed problem for $n$ processes, in which each process starts with a private input value, communicates with other processes, and eventually decides an output value. A Task is Colorless if each process can adopt the input or output value of another process. Colorless Tasks are well studied in the non-anonymous shared-memory model where each process has a distinct identifier that can be used to access a single-writer/multi-reader shared register. In the anonymous case, where processes have no identifiers and communicate through multi-writer/multi-reader registers, there is a recent topological characterization of the Colorless Tasks that are solvable when any number of asynchronous processes may crash. In this paper we study the case where at most $t$ processes may crash, where $1 \le t < n$. We prove that a Colorless Task is $t$-resilient solvable non-anonymously if and only if it is $t$-resilient solvable anonymously. This implies a complete characterization of Colorless anonymous t-resilient asynchronous Task computability.

Pierre Sutra - One of the best experts on this subject based on the ideXlab platform.

  • Anonymous obstruction-free (n,k)-set agreement with n−k+1 atomic read/write registers
    Distributed Computing, 2018
    Co-Authors: Zohir Bouzid, Michel Raynal, Pierre Sutra
    Abstract:

    The k-set agreement problem is a generalization of the consensus problem. Namely, assuming that each pro- cess proposes a value, every non-faulty process must decide one of the proposed values, under the constraint that at most k different values are decided. This is a hard problem in the sense that it cannot be solved in a pure read/write asyn- chronous system, in which k or more processes may crash. One way to sidestep this impossibility result consists in weak- ening the termination property, requiring only that a process decides if it executes alone during a long enough period of time. This is the well-known obstruction-freedom progress condition. Consider a system of n anonymous asynchronous processes that communicate through atomic read/write reg- isters, and such that any number of them may crash. This paper addresses and solves the challenging open problem of designing an obstruction-free k-set agreement algorithm with only (n −k +1) atomic registers. From a shared memory cost point of view, our algorithm is the best algorithm known to date, thereby establishing a new upper bound on the number of registers needed to solve this problem. For the consensus case (k = 1), the proposed algorithm is up to an additive factor of 1 close to the best known lower bound. Further, the paper extends this algorithm to obtain an x-obstruction- free solution to the k-set agreement problem that employs (n − k + x) atomic registers (with 1 ≤ x ≤ k < n), as well as a space-optimal solution for the repeated ver- sion of k-set agreement. Using this last extension, we prove that n registers are enough for every Colorless Task that is obstruction-free solvable with identifiers and any number of registers

  • Anonymous Obstruction-free $(n,k)$-Set Agreement with $n-k+1$ Atomic Read/Write Registers
    Distributed Computing, 2017
    Co-Authors: Zohir Bouzid, Michel Raynal, Pierre Sutra
    Abstract:

    The k-set agreement problem is a generalization of the consensus problem. Namely, assuming that each pro- cess proposes a value, every non-faulty process must decide one of the proposed values, under the constraint that at most k different values are decided. This is a hard problem in the sense that it cannot be solved in a pure read/write asyn- chronous system, in which k or more processes may crash. One way to sidestep this impossibility result consists in weak- ening the termination property, requiring only that a process decides if it executes alone during a long enough period of time. This is the well-known obstruction-freedom progress condition. Consider a system of n anonymous asynchronous processes that communicate through atomic read/write reg- isters, and such that any number of them may crash. This paper addresses and solves the challenging open problem of designing an obstruction-free k-set agreement algorithm with only (n −k +1) atomic registers. From a shared memory cost point of view, our algorithm is the best algorithm known to date, thereby establishing a new upper bound on the number of registers needed to solve this problem. For the consensus case (k = 1), the proposed algorithm is up to an additive factor of 1 close to the best known lower bound. Further, the paper extends this algorithm to obtain an x-obstruction- free solution to the k-set agreement problem that employs (n − k + x) atomic registers (with 1 ≤ x ≤ k < n), as well as a space-optimal solution for the repeated ver- sion of k-set agreement. Using this last extension, we prove that n registers are enough for every Colorless Task that is obstruction-free solvable with identifiers and any number of registers

Sergio Rajsbaum - One of the best experts on this subject based on the ideXlab platform.

  • SIROCCO - A Characterization of t-Resilient Colorless Task Anonymous Solvability
    Structural Information and Communication Complexity, 2018
    Co-Authors: Carole Delporte-gallet, Hugues Fauconnier, Sergio Rajsbaum, Nayuta Yanagisawa
    Abstract:

    One of the central questions in distributed computability is characterizing the Tasks that are solvable in a given system model. In the anonymous case, where processes have no identifiers and communicate through multi-writer/multi-reader registers, there is a recent topological characterization (Yanagisawa 2017) of the Colorless Tasks that are solvable when any number of asynchronous processes may crash. In this paper, we consider the case where at most t asynchronous processes may crash, where \(1\le t

  • A Characterization of t-Resilient Colorless Task Anonymous Solvability
    2018
    Co-Authors: Carole Delporte-gallet, Hugues Fauconnier, Sergio Rajsbaum, Nayuta Yanagisawa
    Abstract:

    One of the central questions in distributed computability is characterizing the Tasks that are solvable in a given system model. In the anonymous case, where processes have no identifiers and communicate through multi-writer/multi-reader registers, there is a recent topologi-cal characterization (Yanagisawa 2017) of the Colorless Tasks that are solvable when any number of asynchronous processes may crash. In this paper, we consider the case where at most t asynchronous processes may crash, where 1 ≤ t < n. We prove that a Colorless Task is t-resilient solvable anonymously if and only if it is t-resilient solvable non-anonymously. We obtain our results through various reductions and simulations that explore how to extend techniques for non-anonymous computation to anonymous one.

  • a characterization of t resilient Colorless Task anonymous solvability
    SIROCCO 2018 - 25th International Colloquium Structural Information and Communication Complexity, 2018
    Co-Authors: Carole Delportegallet, Hugues Fauconnier, Sergio Rajsbaum, Nayuta Yanagisawa
    Abstract:

    One of the central questions in distributed computability is characterizing the Tasks that are solvable in a given system model. In the anonymous case, where processes have no identifiers and communicate through multi-writer/multi-reader registers, there is a recent topological characterization (Yanagisawa 2017) of the Colorless Tasks that are solvable when any number of asynchronous processes may crash. In this paper, we consider the case where at most t asynchronous processes may crash, where \(1\le tColorless Task is t-resilient solvable anonymously if and only if it is t-resilient solvable non-anonymously. We obtain our results through various reductions and simulations that explore how to extend techniques for non-anonymous computation to anonymous one.

  • A characterization of Colorless anonymous t-resilient Task computability.
    arXiv: Distributed Parallel and Cluster Computing, 2017
    Co-Authors: Carole Delporte-gallet, Hugues Fauconnier, Sergio Rajsbaum, Nayuta Yanagisawa
    Abstract:

    A Task is a distributed problem for $n$ processes, in which each process starts with a private input value, communicates with other processes, and eventually decides an output value. A Task is Colorless if each process can adopt the input or output value of another process. Colorless Tasks are well studied in the non-anonymous shared-memory model where each process has a distinct identifier that can be used to access a single-writer/multi-reader shared register. In the anonymous case, where processes have no identifiers and communicate through multi-writer/multi-reader registers, there is a recent topological characterization of the Colorless Tasks that are solvable when any number of asynchronous processes may crash. In this paper we study the case where at most $t$ processes may crash, where $1 \le t < n$. We prove that a Colorless Task is $t$-resilient solvable non-anonymously if and only if it is $t$-resilient solvable anonymously. This implies a complete characterization of Colorless anonymous t-resilient asynchronous Task computability.

  • PODC - Simulations and reductions for Colorless Tasks
    Proceedings of the 2012 ACM symposium on Principles of distributed computing - PODC '12, 2012
    Co-Authors: Maurice Herlihy, Sergio Rajsbaum
    Abstract:

    If one model of computation can simulate another, then the existence (or non-existence) of an algorithm in the simulated model reduces to a related question about the simulating model. The BG-simulation algorithm uses this approach to prove that k-set agreement cannot be solved when t processes can crash, 1≤t≤k, by reduction to the wait-free case, where it is known that n+1 processes cannot solve n-set agreement, and similarly for any other Colorless Task. We give a definition, expressed in the language of combinatorial topology, for what it means for one model of distributed computation to simulate another with respect to the ability to solve Colorless Tasks. This definition is not linked to specific models or specific protocols. We show how to exploit elementary topological arguments to show when a simulation exists, without the need for an explicit construction. We use this approach to generalize the BG-simulation and to unify a number of simulation relations linking various models, some previously known, some not.

Hugues Fauconnier - One of the best experts on this subject based on the ideXlab platform.

  • SIROCCO - A Characterization of t-Resilient Colorless Task Anonymous Solvability
    Structural Information and Communication Complexity, 2018
    Co-Authors: Carole Delporte-gallet, Hugues Fauconnier, Sergio Rajsbaum, Nayuta Yanagisawa
    Abstract:

    One of the central questions in distributed computability is characterizing the Tasks that are solvable in a given system model. In the anonymous case, where processes have no identifiers and communicate through multi-writer/multi-reader registers, there is a recent topological characterization (Yanagisawa 2017) of the Colorless Tasks that are solvable when any number of asynchronous processes may crash. In this paper, we consider the case where at most t asynchronous processes may crash, where \(1\le t

  • A Characterization of t-Resilient Colorless Task Anonymous Solvability
    2018
    Co-Authors: Carole Delporte-gallet, Hugues Fauconnier, Sergio Rajsbaum, Nayuta Yanagisawa
    Abstract:

    One of the central questions in distributed computability is characterizing the Tasks that are solvable in a given system model. In the anonymous case, where processes have no identifiers and communicate through multi-writer/multi-reader registers, there is a recent topologi-cal characterization (Yanagisawa 2017) of the Colorless Tasks that are solvable when any number of asynchronous processes may crash. In this paper, we consider the case where at most t asynchronous processes may crash, where 1 ≤ t < n. We prove that a Colorless Task is t-resilient solvable anonymously if and only if it is t-resilient solvable non-anonymously. We obtain our results through various reductions and simulations that explore how to extend techniques for non-anonymous computation to anonymous one.

  • a characterization of t resilient Colorless Task anonymous solvability
    SIROCCO 2018 - 25th International Colloquium Structural Information and Communication Complexity, 2018
    Co-Authors: Carole Delportegallet, Hugues Fauconnier, Sergio Rajsbaum, Nayuta Yanagisawa
    Abstract:

    One of the central questions in distributed computability is characterizing the Tasks that are solvable in a given system model. In the anonymous case, where processes have no identifiers and communicate through multi-writer/multi-reader registers, there is a recent topological characterization (Yanagisawa 2017) of the Colorless Tasks that are solvable when any number of asynchronous processes may crash. In this paper, we consider the case where at most t asynchronous processes may crash, where \(1\le tColorless Task is t-resilient solvable anonymously if and only if it is t-resilient solvable non-anonymously. We obtain our results through various reductions and simulations that explore how to extend techniques for non-anonymous computation to anonymous one.

  • A characterization of Colorless anonymous t-resilient Task computability.
    arXiv: Distributed Parallel and Cluster Computing, 2017
    Co-Authors: Carole Delporte-gallet, Hugues Fauconnier, Sergio Rajsbaum, Nayuta Yanagisawa
    Abstract:

    A Task is a distributed problem for $n$ processes, in which each process starts with a private input value, communicates with other processes, and eventually decides an output value. A Task is Colorless if each process can adopt the input or output value of another process. Colorless Tasks are well studied in the non-anonymous shared-memory model where each process has a distinct identifier that can be used to access a single-writer/multi-reader shared register. In the anonymous case, where processes have no identifiers and communicate through multi-writer/multi-reader registers, there is a recent topological characterization of the Colorless Tasks that are solvable when any number of asynchronous processes may crash. In this paper we study the case where at most $t$ processes may crash, where $1 \le t < n$. We prove that a Colorless Task is $t$-resilient solvable non-anonymously if and only if it is $t$-resilient solvable anonymously. This implies a complete characterization of Colorless anonymous t-resilient asynchronous Task computability.

Zohir Bouzid - One of the best experts on this subject based on the ideXlab platform.

  • Anonymous obstruction-free (n,k)-set agreement with n−k+1 atomic read/write registers
    Distributed Computing, 2018
    Co-Authors: Zohir Bouzid, Michel Raynal, Pierre Sutra
    Abstract:

    The k-set agreement problem is a generalization of the consensus problem. Namely, assuming that each pro- cess proposes a value, every non-faulty process must decide one of the proposed values, under the constraint that at most k different values are decided. This is a hard problem in the sense that it cannot be solved in a pure read/write asyn- chronous system, in which k or more processes may crash. One way to sidestep this impossibility result consists in weak- ening the termination property, requiring only that a process decides if it executes alone during a long enough period of time. This is the well-known obstruction-freedom progress condition. Consider a system of n anonymous asynchronous processes that communicate through atomic read/write reg- isters, and such that any number of them may crash. This paper addresses and solves the challenging open problem of designing an obstruction-free k-set agreement algorithm with only (n −k +1) atomic registers. From a shared memory cost point of view, our algorithm is the best algorithm known to date, thereby establishing a new upper bound on the number of registers needed to solve this problem. For the consensus case (k = 1), the proposed algorithm is up to an additive factor of 1 close to the best known lower bound. Further, the paper extends this algorithm to obtain an x-obstruction- free solution to the k-set agreement problem that employs (n − k + x) atomic registers (with 1 ≤ x ≤ k < n), as well as a space-optimal solution for the repeated ver- sion of k-set agreement. Using this last extension, we prove that n registers are enough for every Colorless Task that is obstruction-free solvable with identifiers and any number of registers

  • Anonymous Obstruction-free $(n,k)$-Set Agreement with $n-k+1$ Atomic Read/Write Registers
    Distributed Computing, 2017
    Co-Authors: Zohir Bouzid, Michel Raynal, Pierre Sutra
    Abstract:

    The k-set agreement problem is a generalization of the consensus problem. Namely, assuming that each pro- cess proposes a value, every non-faulty process must decide one of the proposed values, under the constraint that at most k different values are decided. This is a hard problem in the sense that it cannot be solved in a pure read/write asyn- chronous system, in which k or more processes may crash. One way to sidestep this impossibility result consists in weak- ening the termination property, requiring only that a process decides if it executes alone during a long enough period of time. This is the well-known obstruction-freedom progress condition. Consider a system of n anonymous asynchronous processes that communicate through atomic read/write reg- isters, and such that any number of them may crash. This paper addresses and solves the challenging open problem of designing an obstruction-free k-set agreement algorithm with only (n −k +1) atomic registers. From a shared memory cost point of view, our algorithm is the best algorithm known to date, thereby establishing a new upper bound on the number of registers needed to solve this problem. For the consensus case (k = 1), the proposed algorithm is up to an additive factor of 1 close to the best known lower bound. Further, the paper extends this algorithm to obtain an x-obstruction- free solution to the k-set agreement problem that employs (n − k + x) atomic registers (with 1 ≤ x ≤ k < n), as well as a space-optimal solution for the repeated ver- sion of k-set agreement. Using this last extension, we prove that n registers are enough for every Colorless Task that is obstruction-free solvable with identifiers and any number of registers