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Related papers: On the Node-Averaged Complexity of Locally Checkab…

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The node-averaged complexity of a distributed algorithm running on a graph $G=(V,E)$ is the average over the times at which the nodes $V$ of $G$ finish their computation and commit to their outputs. We study the node-averaged complexity for…

Distributed, Parallel, and Cluster Computing · Computer Science 2022-08-18 Alkida Balliu , Mohsen Ghaffari , Fabian Kuhn , Dennis Olivetti

In this work we study local computation with advice: the goal is to solve a graph problem $\Pi$ with a distributed algorithm in $T(\Delta)$ communication rounds, for some function $T$ that only depends on the maximum degree $\Delta$ of the…

Distributed, Parallel, and Cluster Computing · Computer Science 2025-08-25 Alkida Balliu , Sebastian Brandt , Fabian Kuhn , Krzysztof Nowicki , Dennis Olivetti , Eva Rotenberg , Jukka Suomela

Over the past 30 years numerous algorithms have been designed for symmetry breaking problems in the LOCAL model, such as maximal matching, MIS, vertex coloring, and edge-coloring. For most problems the best randomized algorithm is at least…

Computational Complexity · Computer Science 2016-04-07 Yi-Jun Chang , Tsvi Kopelowitz , Seth Pettie

Balliu et al. (DISC 2020) classified the hardness of solving binary labeling problems with distributed graph algorithms; in these problems the task is to select a subset of edges in a $2$-colored tree in which white nodes of degree $d$ and…

Distributed, Parallel, and Cluster Computing · Computer Science 2023-12-20 Henrik Lievonen , Timothé Picavet , Jukka Suomela

The study of Locally Checkable Labelings (LCLs) has led to a remarkably precise characterization of the distributed time complexities that can occur on bounded-degree trees. A central feature of this complexity landscape is the existence of…

Distributed, Parallel, and Cluster Computing · Computer Science 2026-02-17 Gustav Schmid

Many graph problems are locally checkable: a solution is globally feasible if it looks valid in all constant-radius neighborhoods. This idea is formalized in the concept of locally checkable labelings (LCLs), introduced by Naor and…

Distributed, Parallel, and Cluster Computing · Computer Science 2019-04-12 Alkida Balliu , Juho Hirvonen , Christoph Lenzen , Dennis Olivetti , Jukka Suomela

We connect three distinct lines of research that have recently explored extensions of the classical LOCAL model of distributed computing: A. distributed quantum computing and non-signaling distributions [e.g. STOC 2024], B.…

A central theme in distributed network algorithms concerns understanding and coping with the issue of locality. Inspired by sequential complexity theory, we focus on a complexity theory for distributed decision problems. In the context of…

Distributed, Parallel, and Cluster Computing · Computer Science 2011-03-04 Pierre Fraigniaud , Amos Korman , David Peleg

The celebrated Time Hierarchy Theorem for Turing machines states, informally, that more problems can be solved given more time. The extent to which a time hierarchy-type theorem holds in the distributed LOCAL model has been open for many…

Distributed, Parallel, and Cluster Computing · Computer Science 2017-04-24 Yi-Jun Chang , Seth Pettie

Locally checkable labeling problems (LCLs) form the foundation of the modern theory of distributed graph algorithms. First introduced in the seminal paper by Naor and Stockmeyer [STOC 1993], these are graph problems that can be described by…

Distributed, Parallel, and Cluster Computing · Computer Science 2026-02-23 Antonio Cruciani , Avinandan Das , Alesya Raevskaya , Jukka Suomela

The Local Computation Algorithm (LCA) model is a popular model in the field of sublinear-time algorithms that measures the complexity of an algorithm by the number of probes the algorithm makes in the neighborhood of one node to determine…

Data Structures and Algorithms · Computer Science 2021-12-06 Sebastian Brandt , Christoph Grunau , Václav Rozhoň

In this paper, we present the first known example of a locally checkable labeling problem (LCL) that admits asymptotic distributed quantum advantage in the LOCAL model of distributed computing: our problem can be solved in $O(\log n)$…

Distributed, Parallel, and Cluster Computing · Computer Science 2025-04-08 Alkida Balliu , Filippo Casagrande , Francesco d'Amore , Massimo Equi , Barbara Keller , Henrik Lievonen , Dennis Olivetti , Gustav Schmid , Jukka Suomela

We present a deterministic algorithm for solving a wide range of dynamic programming problems in trees in $O(\log D)$ rounds in the massively parallel computation model (MPC), with $O(n^\delta)$ words of local memory per machine, for any…

Distributed, Parallel, and Cluster Computing · Computer Science 2023-05-08 Chetan Gupta , Rustam Latypov , Yannic Maus , Shreyas Pai , Simo Särkkä , Jan Studený , Jukka Suomela , Jara Uitto , Hossein Vahidi

We show fast deterministic algorithms for fundamental problems on forests in the challenging low-space regime of the well-known Massive Parallel Computation (MPC) model. A recent breakthrough result by Coy and Czumaj [STOC'22] shows that,…

Distributed, Parallel, and Cluster Computing · Computer Science 2022-11-08 Alkida Balliu , Rustam Latypov , Yannic Maus , Dennis Olivetti , Jara Uitto

We present a complete classification of the distributed computational complexity of local optimization problems in directed cycles for both the deterministic and the randomized LOCAL model. We show that for any local optimization problem…

Distributed, Parallel, and Cluster Computing · Computer Science 2026-03-06 Thomas Boudier , Fabian Kuhn , Augusto Modanese , Ronja Stimpert , Jukka Suomela

Locally Checkable Labeling (LCL) problems are graph problems in which a solution is correct if it satisfies some given constraints in the local neighborhood of each node. Example problems in this class include maximal matching, maximal…

Distributed, Parallel, and Cluster Computing · Computer Science 2022-08-22 Alkida Balliu , Sebastian Brandt , Manuela Fischer , Rustam Latypov , Yannic Maus , Dennis Olivetti , Jara Uitto

Consider a graph problem that is locally checkable but not locally solvable: given a solution we can check that it is feasible by verifying all constant-radius neighborhoods, but to find a solution each node needs to explore the input graph…

Distributed, Parallel, and Cluster Computing · Computer Science 2020-02-19 Will Rosenbaum , Jukka Suomela

While obtaining optimal algorithms for the most important problems in the LOCAL model has been one of the central goals in the area of distributed algorithms since its infancy, tight complexity bounds are elusive for many problems even when…

Distributed, Parallel, and Cluster Computing · Computer Science 2025-05-06 Sebastian Brandt , Ananth Narayanan

We investigate the connections between the fields of distributed computing and measurable combinatorics by considering complexity classes of locally checkable labeling problems on regular forests. We show that the most important…

We prove several new tight distributed lower bounds for classic symmetry breaking graph problems. As a basic tool, we first provide a new insightful proof that any deterministic distributed algorithm that computes a $\Delta$-coloring on…

Distributed, Parallel, and Cluster Computing · Computer Science 2022-06-03 Alkida Balliu , Sebastian Brandt , Fabian Kuhn , Dennis Olivetti