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Robust Estimation for Random Graphs
Proceedings of Thirty Fifth Conference on Learning Theory, PMLR 178:130-166, 2022.
Abstract
We study the problem of robustly estimating the parameter p of an Erdős-Rényi random graph on n nodes, where a γ fraction of nodes may be adversarially corrupted. After showing the deficiencies of canonical estimators, we design a computationally-efficient spectral algorithm which estimates p up to accuracy ˜O(√p(1−p)/n+γ√p(1−p)/√n+γ/n) for γ<1/60. Furthermore, we give an inefficient algorithm with similar accuracy for all γ<1/2, the information-theoretic limit. Finally, we prove a nearly-matching statistical lower bound, showing that the error of our algorithms is optimal up to logarithmic factors.