English

Counting communities in weighted Stochastic Block Models via semidefinite programming

Statistics Theory 2025-02-25 v1 Statistics Theory

Abstract

We consider the problem of estimating the number of communities in a weighted balanced Stochastic Block Model. We construct hypothesis tests based on semidefinite programming and with a statistic coming from a GOE matrix to distinguish between any two candidate numbers of communities. This is possible due to a universality result for a semidefinite programming-based function that we also prove. The tests are then used to form a sequential test to estimate the number of communities. Furthermore, we also construct estimators of the communities themselves.

Keywords

Cite

@article{arxiv.2502.15891,
  title  = {Counting communities in weighted Stochastic Block Models via semidefinite programming},
  author = {Deborah Oliveira and Andressa Cerqueira and Roberto Oliveira},
  journal= {arXiv preprint arXiv:2502.15891},
  year   = {2025}
}

Comments

This is a first draft. Comments are welcome

R2 v1 2026-06-28T21:53:29.068Z