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Local Laws for Sparse Sample Covariance Matrices Without the Truncation Condition

  • F. Götze,
  • A. N. Tikhomirov,
  • D. A. Timushev

摘要

We consider sparse sample covariance matrices \(\frac{1}{n{p}_{n}}{\mathbf{X}\mathbf{X}}^{*},\) 1 n p n X X , where X is a sparse matrix of order n × m with the sparse probability pn. We prove the local Marchenko–Pastur law in some complex domain assuming that npn > logβ n, β > 0, and some (4+δ)-moment condition is fulfilled, δ > 0.