Difference between revisions of "Open Problems:66"
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Suppose we're given access to two distributions $P$ and $Q$ over $[1 \ldots n]$ and wish to test if they are the same or are at least $\epsilon$ apart under the $\ell_1$ distance. Assume that we have access to ''conditional samples'': in other words, a query consists of a set $S \subset [1..n]$ and the output is a sample drawn from the conditional distribution on $A$. In other words, a conditional sample on $P$ given $S$ is drawn from the distribution where | Suppose we're given access to two distributions $P$ and $Q$ over $[1 \ldots n]$ and wish to test if they are the same or are at least $\epsilon$ apart under the $\ell_1$ distance. Assume that we have access to ''conditional samples'': in other words, a query consists of a set $S \subset [1..n]$ and the output is a sample drawn from the conditional distribution on $A$. In other words, a conditional sample on $P$ given $S$ is drawn from the distribution where | ||
| − | $$ \text{Pr}(j) = \begin{ | + | $$ \text{Pr}(j) = \begin{cases} p_j / \sum_{i \in A} p_i & j \in A \\ 0 & \text{otherwise} \end{cases} $$ |
It is known that if one of the distributions is fixed, then a constant ($f(1/\epsilon)$) number of queries suffice to test the distributions. | It is known that if one of the distributions is fixed, then a constant ($f(1/\epsilon)$) number of queries suffice to test the distributions. | ||
What can we say if both distributions are unknown ? | What can we say if both distributions are unknown ? | ||
Revision as of 14:04, 29 May 2014
| Suggested by | Eldar Fischer |
|---|---|
| Source | Bertinoro 2014 |
| Short link | https://sublinear.info/66 |
Suppose we're given access to two distributions $P$ and $Q$ over $[1 \ldots n]$ and wish to test if they are the same or are at least $\epsilon$ apart under the $\ell_1$ distance. Assume that we have access to conditional samples: in other words, a query consists of a set $S \subset [1..n]$ and the output is a sample drawn from the conditional distribution on $A$. In other words, a conditional sample on $P$ given $S$ is drawn from the distribution where
$$ \text{Pr}(j) = \begin{cases} p_j / \sum_{i \in A} p_i & j \in A \\ 0 & \text{otherwise} \end{cases} $$
It is known that if one of the distributions is fixed, then a constant ($f(1/\epsilon)$) number of queries suffice to test the distributions.
What can we say if both distributions are unknown ?
