Graph-Theoretic Limits of Distributed Computation: Entropy, Eigenvalues, and Chromatic Numbers

We address the problem of the distributed computation of arbitrary functions of two correlated sources, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>X</mi><mn>1</mn></msub...

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Bibliographic Details
Main Authors: Mohammad Reza Deylam Salehi, Derya Malak
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Entropy
Subjects:
Online Access:https://www.mdpi.com/1099-4300/27/7/757
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Summary:We address the problem of the distributed computation of arbitrary functions of two correlated sources, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>X</mi><mn>1</mn></msub></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>X</mi><mn>2</mn></msub></semantics></math></inline-formula>, residing in two distributed source nodes, respectively. We exploit the structure of a computation task by coding source characteristic graphs (and multiple instances using the <i>n</i>-fold OR product of this graph with itself). For regular graphs and general graphs, we establish bounds on the optimal rate—characterized by the chromatic entropy for the <i>n</i>-fold graph products—that allows a receiver for asymptotically lossless computation of arbitrary functions over finite fields. For the special class of cycle graphs (i.e., 2-regular graphs), we establish an exact characterization of chromatic numbers and derive bounds on the required rates. Next, focusing on the more general class of <i>d</i>-regular graphs, we establish connections between <i>d</i>-regular graphs and expansion rates for <i>n</i>-fold graph products using graph spectra. Finally, for general graphs, we leverage the Gershgorin Circle Theorem (GCT) to provide a characterization of the spectra, which allows us to derive new bounds on the optimal rate. Our codes leverage the spectra of the computation and provide a graph expansion-based characterization to succinctly capture the computation structure, providing new insights into the problem of distributed computation of arbitrary functions.
ISSN:1099-4300