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Michael Hardy
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Dimension-free sample complexity for the inverse of Gaussian sample covariance?

Suppose I have $m$ samples drawn from a Gaussian in $\mathbb{R}^n$, and need the inverse of the sample covariance $\Sigma_m^{-1}$ to be $\varepsilon$-close to true inverse covariance $\Sigma^{-1}$ (in expectation or (preferably) with high probability):

$$\|\Sigma^{-1}_m-\Sigma^{-1}\| \le \varepsilon \|\Sigma^{-1}\|$$

For the sample covariance it is known that $$\|\Sigma_m-\Sigma\| \le \varepsilon \|\Sigma\|$$ can be achieved with $r=\operatorname{tr} \Sigma/\|\Sigma\|$ (the intrinsic dimension) $$m \approx \varepsilon^{-2} r$$

I wonder if there is anything similar for the inverse covariance?

axk
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