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Tag: sub

  • Fast and Robust: Computationally Efficient Covariance Estimation for Sub-Weibull Vectors

    Fast and Robust: Computationally Efficient Covariance Estimation for Sub-Weibull Vectors arXiv:2512.17632v1 Announce Type: new Abstract: High-dimensional covariance estimation is notoriously sensitive to outliers. While statistically optimal estimators exist for general heavy-tailed distributions, they often rely on computationally expensive techniques like semidefinite programming or iterative M-estimation ($O(d^3)$). In this work, we target the specific regime of…

  • Optimal Subspace Embeddings: Resolving Nelson-Nguyen Conjecture Up to Sub-Polylogarithmic Factors

    Optimal Subspace Embeddings: Resolving Nelson-Nguyen Conjecture Up to Sub-Polylogarithmic Factors arXiv:2508.14234v1 Announce Type: cross Abstract: We give a proof of the conjecture of Nelson and Nguyen [FOCS 2013] on the optimal dimension and sparsity of oblivious subspace embeddings, up to sub-polylogarithmic factors: For any $ngeq d$ and $epsilongeq d^{-O(1)}$, there is a random $tilde O(d/epsilon^2)times…