Difference between revisions of "Open Problems:81"
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For any $\alpha \geq 0$, the ''Rényi entropy of order $\alpha$'' of a probability distribution $p$ over a discrete domain $\Omega$ is defined as | For any $\alpha \geq 0$, the ''Rényi entropy of order $\alpha$'' of a probability distribution $p$ over a discrete domain $\Omega$ is defined as | ||
Revision as of 05:02, 20 October 2017
| Suggested by | Jayadev Acharya |
|---|---|
| Source | FOCS 2017 |
| Short link | https://sublinear.info/81 |
For any $\alpha \geq 0$, the Rényi entropy of order $\alpha$ of a probability distribution $p$ over a discrete domain $\Omega$ is defined as $$ H_\alpha(p) = \frac{1}{1-\alpha}\log\sum_{x\in\Omega} p(x)^\alpha $$ for $\alpha\neq 1$, and $H_1(p) = \lim_{\alpha\to 1} H_\alpha(p)$. In particular, $H_1$ corresponds to the Shannon entropy $H(p)=-\sum_{x\in\Omega} p(x) \log p(x)$. The problem of estimation Rényi entropy of a distribution $p$, given i.i.d. samples from it, was studied in [Acharya-17], where the authors obtain tight bounds for every integer $\alpha\neq 1$, and nearly-tight ones for every non-integer $\alpha \geq 0$. In the later, however, the sample complexity is only known up to a subpolynomial factor: resolving the exact dependence on $\alpha$ and the alphabet size would be interesting.
