Continuity of Energy Functional
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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
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add a comment |
$begingroup$
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!
functional-analysis functions continuity normed-spaces
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$begingroup$
Halo Kak Evan :)
$endgroup$
– Sou
Jan 18 at 4:07
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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
add a comment |
$begingroup$
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!
functional-analysis functions continuity normed-spaces
$endgroup$
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
functional-analysis functions continuity normed-spaces
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
add a comment |
$begingroup$
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
add a comment |
1 Answer
1
active
oldest
votes
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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 $[0,T)$.
$endgroup$
$begingroup$
Thank you very much for your help!
$endgroup$
– Evan William Chandra
Jan 21 at 0:47
add a comment |
Your Answer
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1 Answer
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1 Answer
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$begingroup$
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 $[0,T)$.
$endgroup$
$begingroup$
Thank you very much for your help!
$endgroup$
– Evan William Chandra
Jan 21 at 0:47
add a comment |
$begingroup$
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 $[0,T)$.
$endgroup$
$begingroup$
Thank you very much for your help!
$endgroup$
– Evan William Chandra
Jan 21 at 0:47
add a comment |
$begingroup$
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 $[0,T)$.
$endgroup$
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 $[0,T)$.
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
add a comment |
$begingroup$
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
add a comment |
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$begingroup$
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