Vadim Kosoy added We_are_now_ready_to__.tex  about 8 years ago

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We are now ready to give our central definition, which corresponds to a notion of "expected value" for distributional estimation problems.  \begin{definition}  Fix $\Gamma$ a growth space of type $(2,2)$ and $\mathcal{E}$ and error space of rank 2. Consider $(\mu,f)$ a distributional estimation problem and $P: \Words \xrightarrow{\Gamma} \Rats$ with bounded range. $P$ is called an \emph{\mathcal{E}(\Gamma)-optimal predictor for $(\mu,f)$} when for any $Q: \Words \xrightarrow{\Gamma} \Rats$ there is $\varepsilon \in \mathcal{E}$ s.t.  \begin{equation}  \E_{(x,y) \sim \mu^k \times U^{\R_P(K)}}[(P^{kj}(x,y) - f(x))^2] \leq \E_{(x,y) \sim \mu^k \times U^{\R_Q(K)}}[(Q^{kj}(x,y) - f(x))^2] + \varepsilon^{kj}   \end{equation}  \end{definition}