Planted Bipartite Graph Detection

Fuente: arXiv
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Main Authors: Rotenberg, Asaf, Huleihel, Wasim, Shayevitz, Ofer
Format: Preprint
Published: 2023
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author Rotenberg, Asaf
Huleihel, Wasim
Shayevitz, Ofer
author_facet Rotenberg, Asaf
Huleihel, Wasim
Shayevitz, Ofer
contents We consider the task of detecting a hidden bipartite subgraph in a given random graph. This is formulated as a hypothesis testing problem, under the null hypothesis, the graph is a realization of an Erdős-Rényi random graph over $n$ vertices with edge density $q$. Under the alternative, there exists a planted $k_{\mathsf{R}} \times k_{\mathsf{L}}$ bipartite subgraph with edge density $p>q$. We characterize the statistical and computational barriers for this problem. Specifically, we derive information-theoretic lower bounds, and design and analyze optimal algorithms matching those bounds, in both the dense regime, where $p,q = Θ\left(1\right)$, and the sparse regime where $p,q = Θ\left(n^{-α}\right), α\in \left(0,2\right]$. We also consider the problem of testing in polynomial-time. As is customary in similar structured high-dimensional problems, our model undergoes an "easy-hard-impossible" phase transition and computational constraints penalize the statistical performance. To provide an evidence for this statistical computational gap, we prove computational lower bounds based on the low-degree conjecture, and show that the class of low-degree polynomials algorithms fail in the conjecturally hard region.
format Preprint
id arxiv_https___arxiv_org_abs_2302_03658
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Planted Bipartite Graph Detection
Rotenberg, Asaf
Huleihel, Wasim
Shayevitz, Ofer
Data Structures and Algorithms
Information Theory
Machine Learning
Statistics Theory
We consider the task of detecting a hidden bipartite subgraph in a given random graph. This is formulated as a hypothesis testing problem, under the null hypothesis, the graph is a realization of an Erdős-Rényi random graph over $n$ vertices with edge density $q$. Under the alternative, there exists a planted $k_{\mathsf{R}} \times k_{\mathsf{L}}$ bipartite subgraph with edge density $p>q$. We characterize the statistical and computational barriers for this problem. Specifically, we derive information-theoretic lower bounds, and design and analyze optimal algorithms matching those bounds, in both the dense regime, where $p,q = Θ\left(1\right)$, and the sparse regime where $p,q = Θ\left(n^{-α}\right), α\in \left(0,2\right]$. We also consider the problem of testing in polynomial-time. As is customary in similar structured high-dimensional problems, our model undergoes an "easy-hard-impossible" phase transition and computational constraints penalize the statistical performance. To provide an evidence for this statistical computational gap, we prove computational lower bounds based on the low-degree conjecture, and show that the class of low-degree polynomials algorithms fail in the conjecturally hard region.
title Planted Bipartite Graph Detection
topic Data Structures and Algorithms
Information Theory
Machine Learning
Statistics Theory
url https://arxiv.org/abs/2302.03658