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Community Detection in Sparse Latent Space Models

5488d69dc70749bea05a729bbd6861a6458c2bff

Speaker

Fengnan Gao, Fudan University, China

Time

2020.09.24 09:00-10:00

Venue

Online—ZOOM APP

ZOOM Info

ZOOM Link
Conference ID: 693-763-49625
PIN Code: 253696

Abstract

We show that a simple community detection algorithm originated from stochastic blockmodel literature achieves consistency, and even optimality, for a broad and flexible class of sparse latent space models. The class of models includes latent eigenmodels. The community detection algorithm is based on spectral clustering followed by local refinement via normalized edge counting. The algorithm is easy to implement and attains high accuracy with a low computational budget. The proof of its optimality depends on a neat equivalence between likelihood ratio test and edge counting in a simple vs.~simple hypothesis testing problem that underpins the refinement step, which could be of independent interest. This is joint work with Zongming Ma and Hongsong Yuan.