A PDE Approach to the Problems of Optimality of Expectations

Let (X, Z) be a bivariate random vector. A predictor of X based on Z is just a Borel function g(Z). The problem of "least squares prediction" of X given the observation Z is to find the global minimum point of the functional E[(X − g(Z))2] with respect to all random variables g(Z), where g...

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Main Author: Mahir Hasanov
Format: Article
Language:English
Published: Etamaths Publishing 2023-06-01
Series:International Journal of Analysis and Applications
Online Access:http://etamaths.com/index.php/ijaa/article/view/2824
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author Mahir Hasanov
author_facet Mahir Hasanov
author_sort Mahir Hasanov
collection DOAJ
description Let (X, Z) be a bivariate random vector. A predictor of X based on Z is just a Borel function g(Z). The problem of "least squares prediction" of X given the observation Z is to find the global minimum point of the functional E[(X − g(Z))2] with respect to all random variables g(Z), where g is a Borel function. It is well known that the solution of this problem is the conditional expectation E(X|Z). We also know that, if for a nonnegative smooth function F: R×R → R, arg ming(Z)E[F(X, g(Z))] = E[X|Z], for all X and Z, then F(x, y) is a Bregmann loss function. It is also of interest, for a fixed ϕ to find F (x, y), satisfying, arg ming(Z)E[F(X, g(Z))] = ϕ(E[X|Z]), for all X and Z. In more general setting, a stronger problem is to find F (x, y) satisfying arg miny∈RE[F (X, y)] = ϕ(E[X]), ∀X. We study this problem and develop a partial differential equation (PDE) approach to solution of these problems.
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spelling doaj.art-9251ca2cb7d64b56ad50bd58e3097ed92023-06-25T06:29:46ZengEtamaths PublishingInternational Journal of Analysis and Applications2291-86392023-06-0121575710.28924/2291-8639-21-2023-572209A PDE Approach to the Problems of Optimality of ExpectationsMahir Hasanov0a:1:{s:5:"en_US";s:18:"Beykent University";}Let (X, Z) be a bivariate random vector. A predictor of X based on Z is just a Borel function g(Z). The problem of "least squares prediction" of X given the observation Z is to find the global minimum point of the functional E[(X − g(Z))2] with respect to all random variables g(Z), where g is a Borel function. It is well known that the solution of this problem is the conditional expectation E(X|Z). We also know that, if for a nonnegative smooth function F: R×R → R, arg ming(Z)E[F(X, g(Z))] = E[X|Z], for all X and Z, then F(x, y) is a Bregmann loss function. It is also of interest, for a fixed ϕ to find F (x, y), satisfying, arg ming(Z)E[F(X, g(Z))] = ϕ(E[X|Z]), for all X and Z. In more general setting, a stronger problem is to find F (x, y) satisfying arg miny∈RE[F (X, y)] = ϕ(E[X]), ∀X. We study this problem and develop a partial differential equation (PDE) approach to solution of these problems.http://etamaths.com/index.php/ijaa/article/view/2824
spellingShingle Mahir Hasanov
A PDE Approach to the Problems of Optimality of Expectations
International Journal of Analysis and Applications
title A PDE Approach to the Problems of Optimality of Expectations
title_full A PDE Approach to the Problems of Optimality of Expectations
title_fullStr A PDE Approach to the Problems of Optimality of Expectations
title_full_unstemmed A PDE Approach to the Problems of Optimality of Expectations
title_short A PDE Approach to the Problems of Optimality of Expectations
title_sort pde approach to the problems of optimality of expectations
url http://etamaths.com/index.php/ijaa/article/view/2824
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