Counting Stars is Constant-Degree Optimal For Detecting Any Planted Subgraph

Fuente: arXiv
Salvato in:
Dettagli Bibliografici
Autori principali: Yu, Xifan, Zadik, Ilias, Zhang, Peiyuan
Natura: Preprint
Pubblicazione: 2024
Soggetti:
Accesso online:
Tags: Aggiungi Tag
Nessun Tag, puoi essere il primo ad aggiungerne!!
_version_ 1866910384459350016
author Yu, Xifan
Zadik, Ilias
Zhang, Peiyuan
author_facet Yu, Xifan
Zadik, Ilias
Zhang, Peiyuan
contents We study the computational limits of the following general hypothesis testing problem. Let H=H_n be an \emph{arbitrary} undirected graph on n vertices. We study the detection task between a ``null'' Erdős-Rényi random graph G(n,p) and a ``planted'' random graph which is the union of G(n,p) together with a random copy of H=H_n. Our notion of planted model is a generalization of a plethora of recently studied models initiated with the study of the planted clique model (Jerrum 1992), which corresponds to the special case where H is a k-clique and p=1/2. Over the last decade, several papers have studied the power of low-degree polynomials for limited choices of H's in the above task. In this work, we adopt a unifying perspective and characterize the power of \emph{constant degree} polynomials for the detection task, when \emph{H=H_n is any arbitrary graph} and for \emph{any p=Ω(1).} Perhaps surprisingly, we prove that the optimal constant degree polynomial is always given by simply \emph{counting stars} in the input random graph. As a direct corollary, we conclude that the class of constant-degree polynomials is only able to ``sense'' the degree distribution of the planted graph H, and no other graph theoretic property of it.
format Preprint
id arxiv_https___arxiv_org_abs_2403_17766
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Counting Stars is Constant-Degree Optimal For Detecting Any Planted Subgraph
Yu, Xifan
Zadik, Ilias
Zhang, Peiyuan
Statistics Theory
Computational Complexity
Data Structures and Algorithms
We study the computational limits of the following general hypothesis testing problem. Let H=H_n be an \emph{arbitrary} undirected graph on n vertices. We study the detection task between a ``null'' Erdős-Rényi random graph G(n,p) and a ``planted'' random graph which is the union of G(n,p) together with a random copy of H=H_n. Our notion of planted model is a generalization of a plethora of recently studied models initiated with the study of the planted clique model (Jerrum 1992), which corresponds to the special case where H is a k-clique and p=1/2. Over the last decade, several papers have studied the power of low-degree polynomials for limited choices of H's in the above task. In this work, we adopt a unifying perspective and characterize the power of \emph{constant degree} polynomials for the detection task, when \emph{H=H_n is any arbitrary graph} and for \emph{any p=Ω(1).} Perhaps surprisingly, we prove that the optimal constant degree polynomial is always given by simply \emph{counting stars} in the input random graph. As a direct corollary, we conclude that the class of constant-degree polynomials is only able to ``sense'' the degree distribution of the planted graph H, and no other graph theoretic property of it.
title Counting Stars is Constant-Degree Optimal For Detecting Any Planted Subgraph
topic Statistics Theory
Computational Complexity
Data Structures and Algorithms
url https://arxiv.org/abs/2403.17766