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Apple Machine Learning Research |
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We study the problem of differentially private stochastic convex optimization (DP-SCO) with heavy-tailed gradients, where we assume a kthk^{\text{th}}kth-moment bound on the Lipschitz constants of sample functions, rather than a uniform bound. We propose a new reduction-based approach that enables us to obtain the first optimal rates (up to logarithmic factors) in the heavy-tailed setting, achieving error G2⋅1n+Gk⋅(dnε)1−1kG_2 \cdot \frac 1 {\sqrt n} + G_k \cdot (\frac{\sqrt d}{n\varepsilon})^{1 - \frac 1 k}G2⋅n1+Gk⋅(nεd)1−k1 under (ε,δ)(\varepsilon, \delta)(ε,δ)-approximate…