Different notation $dP(x)$ and $P(dx)$












1












$begingroup$


Quick question that has been bugging me for a while: I have come across both the notation $dP(x)$ as well as $P(dx)$ when looking at the $mathbb E[X]$ where $X$ is a continuous real random variable. Am I missing an important concept as to why both are used, rather than just one? Or are these notations simply equivalent?










share|cite|improve this question









$endgroup$












  • $begingroup$
    Neither of them means anything in their own except that the integral is with respect to the measure $P.$ In fact, you can drop the "$dx$" symbols everywhere and simply write $mathbf{E}(X) = intlimits_Omega X dP.$
    $endgroup$
    – Will M.
    Jan 29 at 20:27










  • $begingroup$
    They come handy when you have a function of two variables, say $x in Omega$ and $t in mathrm{T}$ and the measure $P$ is on $Omega.$ But even then the fact that $P$ is defined on $Omega$ should suffice...
    $endgroup$
    – Will M.
    Jan 29 at 20:28
















1












$begingroup$


Quick question that has been bugging me for a while: I have come across both the notation $dP(x)$ as well as $P(dx)$ when looking at the $mathbb E[X]$ where $X$ is a continuous real random variable. Am I missing an important concept as to why both are used, rather than just one? Or are these notations simply equivalent?










share|cite|improve this question









$endgroup$












  • $begingroup$
    Neither of them means anything in their own except that the integral is with respect to the measure $P.$ In fact, you can drop the "$dx$" symbols everywhere and simply write $mathbf{E}(X) = intlimits_Omega X dP.$
    $endgroup$
    – Will M.
    Jan 29 at 20:27










  • $begingroup$
    They come handy when you have a function of two variables, say $x in Omega$ and $t in mathrm{T}$ and the measure $P$ is on $Omega.$ But even then the fact that $P$ is defined on $Omega$ should suffice...
    $endgroup$
    – Will M.
    Jan 29 at 20:28














1












1








1


1



$begingroup$


Quick question that has been bugging me for a while: I have come across both the notation $dP(x)$ as well as $P(dx)$ when looking at the $mathbb E[X]$ where $X$ is a continuous real random variable. Am I missing an important concept as to why both are used, rather than just one? Or are these notations simply equivalent?










share|cite|improve this question









$endgroup$




Quick question that has been bugging me for a while: I have come across both the notation $dP(x)$ as well as $P(dx)$ when looking at the $mathbb E[X]$ where $X$ is a continuous real random variable. Am I missing an important concept as to why both are used, rather than just one? Or are these notations simply equivalent?







probability probability-theory measure-theory random-variables






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Jan 29 at 17:48









SABOYSABOY

592311




592311












  • $begingroup$
    Neither of them means anything in their own except that the integral is with respect to the measure $P.$ In fact, you can drop the "$dx$" symbols everywhere and simply write $mathbf{E}(X) = intlimits_Omega X dP.$
    $endgroup$
    – Will M.
    Jan 29 at 20:27










  • $begingroup$
    They come handy when you have a function of two variables, say $x in Omega$ and $t in mathrm{T}$ and the measure $P$ is on $Omega.$ But even then the fact that $P$ is defined on $Omega$ should suffice...
    $endgroup$
    – Will M.
    Jan 29 at 20:28


















  • $begingroup$
    Neither of them means anything in their own except that the integral is with respect to the measure $P.$ In fact, you can drop the "$dx$" symbols everywhere and simply write $mathbf{E}(X) = intlimits_Omega X dP.$
    $endgroup$
    – Will M.
    Jan 29 at 20:27










  • $begingroup$
    They come handy when you have a function of two variables, say $x in Omega$ and $t in mathrm{T}$ and the measure $P$ is on $Omega.$ But even then the fact that $P$ is defined on $Omega$ should suffice...
    $endgroup$
    – Will M.
    Jan 29 at 20:28
















$begingroup$
Neither of them means anything in their own except that the integral is with respect to the measure $P.$ In fact, you can drop the "$dx$" symbols everywhere and simply write $mathbf{E}(X) = intlimits_Omega X dP.$
$endgroup$
– Will M.
Jan 29 at 20:27




$begingroup$
Neither of them means anything in their own except that the integral is with respect to the measure $P.$ In fact, you can drop the "$dx$" symbols everywhere and simply write $mathbf{E}(X) = intlimits_Omega X dP.$
$endgroup$
– Will M.
Jan 29 at 20:27












$begingroup$
They come handy when you have a function of two variables, say $x in Omega$ and $t in mathrm{T}$ and the measure $P$ is on $Omega.$ But even then the fact that $P$ is defined on $Omega$ should suffice...
$endgroup$
– Will M.
Jan 29 at 20:28




$begingroup$
They come handy when you have a function of two variables, say $x in Omega$ and $t in mathrm{T}$ and the measure $P$ is on $Omega.$ But even then the fact that $P$ is defined on $Omega$ should suffice...
$endgroup$
– Will M.
Jan 29 at 20:28










0






active

oldest

votes












Your Answer





StackExchange.ifUsing("editor", function () {
return StackExchange.using("mathjaxEditing", function () {
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
});
});
}, "mathjax-editing");

StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "69"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});


}
});














draft saved

draft discarded


















StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3092499%2fdifferent-notation-dpx-and-pdx%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown

























0






active

oldest

votes








0






active

oldest

votes









active

oldest

votes






active

oldest

votes
















draft saved

draft discarded




















































Thanks for contributing an answer to Mathematics Stack Exchange!


  • Please be sure to answer the question. Provide details and share your research!

But avoid



  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.


Use MathJax to format equations. MathJax reference.


To learn more, see our tips on writing great answers.




draft saved


draft discarded














StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3092499%2fdifferent-notation-dpx-and-pdx%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown





















































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown

































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown







Popular posts from this blog

'app-layout' is not a known element: how to share Component with different Modules

android studio warns about leanback feature tag usage required on manifest while using Unity exported app?

WPF add header to Image with URL pettitions [duplicate]