Lebesgue outer measure regularity
$begingroup$
In $mathbb{R}$, the outer regularity of Lebesgue measure gives $m^*(A)=inf{m(A)mid E text{ is open and } A subset E}$.
Can we replace $E$ as measurable sets instead of open sets? I am not able to prove it. Looking for some hints. Thanks in advance.
measure-theory lebesgue-measure outer-measure
$endgroup$
add a comment |
$begingroup$
In $mathbb{R}$, the outer regularity of Lebesgue measure gives $m^*(A)=inf{m(A)mid E text{ is open and } A subset E}$.
Can we replace $E$ as measurable sets instead of open sets? I am not able to prove it. Looking for some hints. Thanks in advance.
measure-theory lebesgue-measure outer-measure
$endgroup$
add a comment |
$begingroup$
In $mathbb{R}$, the outer regularity of Lebesgue measure gives $m^*(A)=inf{m(A)mid E text{ is open and } A subset E}$.
Can we replace $E$ as measurable sets instead of open sets? I am not able to prove it. Looking for some hints. Thanks in advance.
measure-theory lebesgue-measure outer-measure
$endgroup$
In $mathbb{R}$, the outer regularity of Lebesgue measure gives $m^*(A)=inf{m(A)mid E text{ is open and } A subset E}$.
Can we replace $E$ as measurable sets instead of open sets? I am not able to prove it. Looking for some hints. Thanks in advance.
measure-theory lebesgue-measure outer-measure
measure-theory lebesgue-measure outer-measure
edited Jan 10 at 16:22
amWhy
1
1
asked Jan 31 '17 at 15:10
ArindamArindam
338213
338213
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
$begingroup$
You can but the result is somewhat trivial. Since every open set is Lebesgue measurable, we have
$$inf{m(E)mid E text{ is measurable},; A subseteq E} leq inf{m(E)mid E text{ is open}, ;Asubseteq E} = m^*(A).$$
This follows because the left infimum has a greater range.
By monotonicity, $m^{*}(A) leq m^{*}(E) = m(E)$ holds for all measurable $E$.
Therefore, we have
$$m^*(A) leq inf{m(E)mid E text{ is measurable}, A subseteq E}$$
$endgroup$
add a comment |
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
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f2122575%2flebesgue-outer-measure-regularity%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
You can but the result is somewhat trivial. Since every open set is Lebesgue measurable, we have
$$inf{m(E)mid E text{ is measurable},; A subseteq E} leq inf{m(E)mid E text{ is open}, ;Asubseteq E} = m^*(A).$$
This follows because the left infimum has a greater range.
By monotonicity, $m^{*}(A) leq m^{*}(E) = m(E)$ holds for all measurable $E$.
Therefore, we have
$$m^*(A) leq inf{m(E)mid E text{ is measurable}, A subseteq E}$$
$endgroup$
add a comment |
$begingroup$
You can but the result is somewhat trivial. Since every open set is Lebesgue measurable, we have
$$inf{m(E)mid E text{ is measurable},; A subseteq E} leq inf{m(E)mid E text{ is open}, ;Asubseteq E} = m^*(A).$$
This follows because the left infimum has a greater range.
By monotonicity, $m^{*}(A) leq m^{*}(E) = m(E)$ holds for all measurable $E$.
Therefore, we have
$$m^*(A) leq inf{m(E)mid E text{ is measurable}, A subseteq E}$$
$endgroup$
add a comment |
$begingroup$
You can but the result is somewhat trivial. Since every open set is Lebesgue measurable, we have
$$inf{m(E)mid E text{ is measurable},; A subseteq E} leq inf{m(E)mid E text{ is open}, ;Asubseteq E} = m^*(A).$$
This follows because the left infimum has a greater range.
By monotonicity, $m^{*}(A) leq m^{*}(E) = m(E)$ holds for all measurable $E$.
Therefore, we have
$$m^*(A) leq inf{m(E)mid E text{ is measurable}, A subseteq E}$$
$endgroup$
You can but the result is somewhat trivial. Since every open set is Lebesgue measurable, we have
$$inf{m(E)mid E text{ is measurable},; A subseteq E} leq inf{m(E)mid E text{ is open}, ;Asubseteq E} = m^*(A).$$
This follows because the left infimum has a greater range.
By monotonicity, $m^{*}(A) leq m^{*}(E) = m(E)$ holds for all measurable $E$.
Therefore, we have
$$m^*(A) leq inf{m(E)mid E text{ is measurable}, A subseteq E}$$
edited Jan 10 at 16:06
amWhy
1
1
answered Jan 31 '17 at 15:14
Henricus V.Henricus V.
15.1k22048
15.1k22048
add a comment |
add a comment |
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.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f2122575%2flebesgue-outer-measure-regularity%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
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