Continuity of Energy Functional












3












$begingroup$


Let $u : Omega times [0,T]$ be a function such that $u in C^{2,1}(Omega times [0,T])cap C^{1}((0,T);L^{2}(Omega))cap C([0,T);H_{0}^{1}(Omega))$ for $Omega subset mathbb{R}$ an unbounded domain.



In order to clarify the meaning of the notation, I will explain some notations mentioned above.

1. $C^{2,1}(Omega times [0,T])$ : the function is twice differentiable with respect to spatial domain and once differentiable with respect to time domain.

2. $C^{1}((0,T);L^{2}(Omega))$ : for any fixed $t in (0,T)$, $u(, ., ,t)in L^{2}(Omega)$ and the mapping is once differentiable

3. $C([0,T);H_{0}^{1}(Omega))$ : for any fixed $t in [0,T), u(, ., ,t)in H_{0}^{1}(Omega)$ and the mapping is continuous.



So now I define, a functional $F[, .,] = ||, .,||_{L^{p}(Omega)}^{p}$ ($2<p<infty$) so that I have $F[u(,.,)] : [0,T)tomathbb{R}$



What I want to show is $F[u(,.,)] in C([0,T);mathbb{R})$ but I am not sure how to ensure that $||,.,||_{L^{p}(Omega)}$ is finite since $Omega$ is unbounded and thus I cannot use the embedding of $L^{p}$ to $L^{2}$ for $2<p<infty$. Furthermore, the dimension $n=1$ so I cannot use any embedding inequality here.



Any help is much appreciated! Thank you!










share|cite|improve this question









$endgroup$












  • $begingroup$
    Halo Kak Evan :)
    $endgroup$
    – Sou
    Jan 18 at 4:07










  • $begingroup$
    Hello there, since this is an English Forum. I'd rather not to speak in Indonesian Language. I assume I know you from my undergraduate university?
    $endgroup$
    – Evan William Chandra
    Jan 18 at 4:11










  • $begingroup$
    Yes. Just saying hello.
    $endgroup$
    – Sou
    Jan 18 at 4:12
















3












$begingroup$


Let $u : Omega times [0,T]$ be a function such that $u in C^{2,1}(Omega times [0,T])cap C^{1}((0,T);L^{2}(Omega))cap C([0,T);H_{0}^{1}(Omega))$ for $Omega subset mathbb{R}$ an unbounded domain.



In order to clarify the meaning of the notation, I will explain some notations mentioned above.

1. $C^{2,1}(Omega times [0,T])$ : the function is twice differentiable with respect to spatial domain and once differentiable with respect to time domain.

2. $C^{1}((0,T);L^{2}(Omega))$ : for any fixed $t in (0,T)$, $u(, ., ,t)in L^{2}(Omega)$ and the mapping is once differentiable

3. $C([0,T);H_{0}^{1}(Omega))$ : for any fixed $t in [0,T), u(, ., ,t)in H_{0}^{1}(Omega)$ and the mapping is continuous.



So now I define, a functional $F[, .,] = ||, .,||_{L^{p}(Omega)}^{p}$ ($2<p<infty$) so that I have $F[u(,.,)] : [0,T)tomathbb{R}$



What I want to show is $F[u(,.,)] in C([0,T);mathbb{R})$ but I am not sure how to ensure that $||,.,||_{L^{p}(Omega)}$ is finite since $Omega$ is unbounded and thus I cannot use the embedding of $L^{p}$ to $L^{2}$ for $2<p<infty$. Furthermore, the dimension $n=1$ so I cannot use any embedding inequality here.



Any help is much appreciated! Thank you!










share|cite|improve this question









$endgroup$












  • $begingroup$
    Halo Kak Evan :)
    $endgroup$
    – Sou
    Jan 18 at 4:07










  • $begingroup$
    Hello there, since this is an English Forum. I'd rather not to speak in Indonesian Language. I assume I know you from my undergraduate university?
    $endgroup$
    – Evan William Chandra
    Jan 18 at 4:11










  • $begingroup$
    Yes. Just saying hello.
    $endgroup$
    – Sou
    Jan 18 at 4:12














3












3








3





$begingroup$


Let $u : Omega times [0,T]$ be a function such that $u in C^{2,1}(Omega times [0,T])cap C^{1}((0,T);L^{2}(Omega))cap C([0,T);H_{0}^{1}(Omega))$ for $Omega subset mathbb{R}$ an unbounded domain.



In order to clarify the meaning of the notation, I will explain some notations mentioned above.

1. $C^{2,1}(Omega times [0,T])$ : the function is twice differentiable with respect to spatial domain and once differentiable with respect to time domain.

2. $C^{1}((0,T);L^{2}(Omega))$ : for any fixed $t in (0,T)$, $u(, ., ,t)in L^{2}(Omega)$ and the mapping is once differentiable

3. $C([0,T);H_{0}^{1}(Omega))$ : for any fixed $t in [0,T), u(, ., ,t)in H_{0}^{1}(Omega)$ and the mapping is continuous.



So now I define, a functional $F[, .,] = ||, .,||_{L^{p}(Omega)}^{p}$ ($2<p<infty$) so that I have $F[u(,.,)] : [0,T)tomathbb{R}$



What I want to show is $F[u(,.,)] in C([0,T);mathbb{R})$ but I am not sure how to ensure that $||,.,||_{L^{p}(Omega)}$ is finite since $Omega$ is unbounded and thus I cannot use the embedding of $L^{p}$ to $L^{2}$ for $2<p<infty$. Furthermore, the dimension $n=1$ so I cannot use any embedding inequality here.



Any help is much appreciated! Thank you!










share|cite|improve this question









$endgroup$




Let $u : Omega times [0,T]$ be a function such that $u in C^{2,1}(Omega times [0,T])cap C^{1}((0,T);L^{2}(Omega))cap C([0,T);H_{0}^{1}(Omega))$ for $Omega subset mathbb{R}$ an unbounded domain.



In order to clarify the meaning of the notation, I will explain some notations mentioned above.

1. $C^{2,1}(Omega times [0,T])$ : the function is twice differentiable with respect to spatial domain and once differentiable with respect to time domain.

2. $C^{1}((0,T);L^{2}(Omega))$ : for any fixed $t in (0,T)$, $u(, ., ,t)in L^{2}(Omega)$ and the mapping is once differentiable

3. $C([0,T);H_{0}^{1}(Omega))$ : for any fixed $t in [0,T), u(, ., ,t)in H_{0}^{1}(Omega)$ and the mapping is continuous.



So now I define, a functional $F[, .,] = ||, .,||_{L^{p}(Omega)}^{p}$ ($2<p<infty$) so that I have $F[u(,.,)] : [0,T)tomathbb{R}$



What I want to show is $F[u(,.,)] in C([0,T);mathbb{R})$ but I am not sure how to ensure that $||,.,||_{L^{p}(Omega)}$ is finite since $Omega$ is unbounded and thus I cannot use the embedding of $L^{p}$ to $L^{2}$ for $2<p<infty$. Furthermore, the dimension $n=1$ so I cannot use any embedding inequality here.



Any help is much appreciated! Thank you!







functional-analysis functions continuity normed-spaces






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Jan 18 at 3:35









Evan William ChandraEvan William Chandra

619313




619313












  • $begingroup$
    Halo Kak Evan :)
    $endgroup$
    – Sou
    Jan 18 at 4:07










  • $begingroup$
    Hello there, since this is an English Forum. I'd rather not to speak in Indonesian Language. I assume I know you from my undergraduate university?
    $endgroup$
    – Evan William Chandra
    Jan 18 at 4:11










  • $begingroup$
    Yes. Just saying hello.
    $endgroup$
    – Sou
    Jan 18 at 4:12


















  • $begingroup$
    Halo Kak Evan :)
    $endgroup$
    – Sou
    Jan 18 at 4:07










  • $begingroup$
    Hello there, since this is an English Forum. I'd rather not to speak in Indonesian Language. I assume I know you from my undergraduate university?
    $endgroup$
    – Evan William Chandra
    Jan 18 at 4:11










  • $begingroup$
    Yes. Just saying hello.
    $endgroup$
    – Sou
    Jan 18 at 4:12
















$begingroup$
Halo Kak Evan :)
$endgroup$
– Sou
Jan 18 at 4:07




$begingroup$
Halo Kak Evan :)
$endgroup$
– Sou
Jan 18 at 4:07












$begingroup$
Hello there, since this is an English Forum. I'd rather not to speak in Indonesian Language. I assume I know you from my undergraduate university?
$endgroup$
– Evan William Chandra
Jan 18 at 4:11




$begingroup$
Hello there, since this is an English Forum. I'd rather not to speak in Indonesian Language. I assume I know you from my undergraduate university?
$endgroup$
– Evan William Chandra
Jan 18 at 4:11












$begingroup$
Yes. Just saying hello.
$endgroup$
– Sou
Jan 18 at 4:12




$begingroup$
Yes. Just saying hello.
$endgroup$
– Sou
Jan 18 at 4:12










1 Answer
1






active

oldest

votes


















1












$begingroup$

What you need is the Sobolev embedding $H^1_0(Omega)hookrightarrow L^infty(Omega)$ (see for example Theorem 8.8 in Functional Analysis, Sobolev Spaces and Partial Differential Equations by Brezis). It implies $uin C([0,T);L^2(Omega))cap C([0,T);L^infty(Omega))$. Together with the interpolation inequality
$$
|f|_p^pleq |f|_2^{2}|f|_infty^{p-2}
$$

this yields $uin C([0,T);L^p(Omega))$. In particular, $F$ is continuous on $[0,T)$.






share|cite|improve this answer









$endgroup$













  • $begingroup$
    Thank you very much for your help!
    $endgroup$
    – Evan William Chandra
    Jan 21 at 0:47











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%2f3077806%2fcontinuity-of-energy-functional%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









1












$begingroup$

What you need is the Sobolev embedding $H^1_0(Omega)hookrightarrow L^infty(Omega)$ (see for example Theorem 8.8 in Functional Analysis, Sobolev Spaces and Partial Differential Equations by Brezis). It implies $uin C([0,T);L^2(Omega))cap C([0,T);L^infty(Omega))$. Together with the interpolation inequality
$$
|f|_p^pleq |f|_2^{2}|f|_infty^{p-2}
$$

this yields $uin C([0,T);L^p(Omega))$. In particular, $F$ is continuous on $[0,T)$.






share|cite|improve this answer









$endgroup$













  • $begingroup$
    Thank you very much for your help!
    $endgroup$
    – Evan William Chandra
    Jan 21 at 0:47
















1












$begingroup$

What you need is the Sobolev embedding $H^1_0(Omega)hookrightarrow L^infty(Omega)$ (see for example Theorem 8.8 in Functional Analysis, Sobolev Spaces and Partial Differential Equations by Brezis). It implies $uin C([0,T);L^2(Omega))cap C([0,T);L^infty(Omega))$. Together with the interpolation inequality
$$
|f|_p^pleq |f|_2^{2}|f|_infty^{p-2}
$$

this yields $uin C([0,T);L^p(Omega))$. In particular, $F$ is continuous on $[0,T)$.






share|cite|improve this answer









$endgroup$













  • $begingroup$
    Thank you very much for your help!
    $endgroup$
    – Evan William Chandra
    Jan 21 at 0:47














1












1








1





$begingroup$

What you need is the Sobolev embedding $H^1_0(Omega)hookrightarrow L^infty(Omega)$ (see for example Theorem 8.8 in Functional Analysis, Sobolev Spaces and Partial Differential Equations by Brezis). It implies $uin C([0,T);L^2(Omega))cap C([0,T);L^infty(Omega))$. Together with the interpolation inequality
$$
|f|_p^pleq |f|_2^{2}|f|_infty^{p-2}
$$

this yields $uin C([0,T);L^p(Omega))$. In particular, $F$ is continuous on $[0,T)$.






share|cite|improve this answer









$endgroup$



What you need is the Sobolev embedding $H^1_0(Omega)hookrightarrow L^infty(Omega)$ (see for example Theorem 8.8 in Functional Analysis, Sobolev Spaces and Partial Differential Equations by Brezis). It implies $uin C([0,T);L^2(Omega))cap C([0,T);L^infty(Omega))$. Together with the interpolation inequality
$$
|f|_p^pleq |f|_2^{2}|f|_infty^{p-2}
$$

this yields $uin C([0,T);L^p(Omega))$. In particular, $F$ is continuous on $[0,T)$.







share|cite|improve this answer












share|cite|improve this answer



share|cite|improve this answer










answered Jan 18 at 12:42









MaoWaoMaoWao

3,153617




3,153617












  • $begingroup$
    Thank you very much for your help!
    $endgroup$
    – Evan William Chandra
    Jan 21 at 0:47


















  • $begingroup$
    Thank you very much for your help!
    $endgroup$
    – Evan William Chandra
    Jan 21 at 0:47
















$begingroup$
Thank you very much for your help!
$endgroup$
– Evan William Chandra
Jan 21 at 0:47




$begingroup$
Thank you very much for your help!
$endgroup$
– Evan William Chandra
Jan 21 at 0:47


















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%2f3077806%2fcontinuity-of-energy-functional%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

Mario Kart Wii

The Binding of Isaac: Rebirth/Afterbirth

Dobbiaco