The Complexity of the Distributed Constraint Satisfaction Problem
Year: 2020
Type: preprint
Abstract: We study the complexity of the Distributed Constraint Satisfaction Problem (DCSP) on a synchronous, anonymous network from a theoretical standpoint. In this setting, variables and constraints are controlled by agents which communicate with each other by sending messages through fixed communication channels. Our results endorse the well-known fact from classical CSPs that the complexity of fixed-template computational problems depends on the template's invariance under certain operations. Specifically, we show that DCSP($Γ$) is polynomial-time tractable if and only if $Γ$ is invariant under symmetric polymorphisms of all arities. Otherwise, there are no algorithms that solve DCSP($Γ$) in finite time. We also show that the same condition holds for the search variant of DCSP. Collaterally, our results unveil a feature of the processes' neighbourhood in a distributed network, its iterated degree, which plays a major role in the analysis. We explore this notion establishing a tight connection with the basic linear programming relaxation of a CSP.
Source: arXiv (Cornell University)
Authors: Butti, Silvia, Dalmau, Victor
Institution: Universitat Pompeu Fabra
Language: English
Subfield: Computer Networks and Communications
Field: Computer Science
Domain: Physical Sciences
Open Access status: green
Funder: European Commission
OpenAlex ID: W4287704591