Method of characteristics for the Beltrami equation when $mu$ is real analytic
up vote
1
down vote
favorite
I am reading a proof of the measurable mapping theorem which shows the existence of a solution to the Beltrami equation in the simple case when $mu in L^{infty}(mathbb{C})$ is real analytic (due to Gauss)
begin{equation}
(1-mu(x,y))frac{partial{f}}{partial{x}}+ i(1+mu(x,y)))frac{partial{f}}{partial{y}}=0
tag{4.5.8}
end{equation}
From what I understand, we are looking for a curve $(x(t), y(t))$ which satisfies
$$frac{dx}{dt}=1-mu(x,y)$$ and
$$frac{dy}{dt}=i(1+mu(x,y))$$.
The author then points out that such a curve would satisfy
$$frac{dy}{dx}= ifrac{1+u}{1-u} tag{*}$$
I wanted to understand how one goes from the system of ODE's above to (*). Does $mu$ being real analytic imply that there is a solution to the system above
Furthermore, if there is such a solution, the inverse function theorem tells us that the solution is a local homeomorphism, can we say anything about uniqueness just from the ODE theory?
pde teichmueller-theory
add a comment |
up vote
1
down vote
favorite
I am reading a proof of the measurable mapping theorem which shows the existence of a solution to the Beltrami equation in the simple case when $mu in L^{infty}(mathbb{C})$ is real analytic (due to Gauss)
begin{equation}
(1-mu(x,y))frac{partial{f}}{partial{x}}+ i(1+mu(x,y)))frac{partial{f}}{partial{y}}=0
tag{4.5.8}
end{equation}
From what I understand, we are looking for a curve $(x(t), y(t))$ which satisfies
$$frac{dx}{dt}=1-mu(x,y)$$ and
$$frac{dy}{dt}=i(1+mu(x,y))$$.
The author then points out that such a curve would satisfy
$$frac{dy}{dx}= ifrac{1+u}{1-u} tag{*}$$
I wanted to understand how one goes from the system of ODE's above to (*). Does $mu$ being real analytic imply that there is a solution to the system above
Furthermore, if there is such a solution, the inverse function theorem tells us that the solution is a local homeomorphism, can we say anything about uniqueness just from the ODE theory?
pde teichmueller-theory
I suspect your third equation should read $dy/dt = i(1 + mu(x, y))$, not $dx/dt = i(1 + mu(x, y))$. Could I be right? Cheers!
– Robert Lewis
Nov 21 at 17:32
1
Yes! Thank you!
– user135520
Nov 21 at 17:57
Glad to help out, my friend!
– Robert Lewis
Nov 21 at 18:02
1
Are you asking how $$x' = 1 - mu, quad y' = i(1+mu) implies frac{y'}{x'} = frac{dy}{dt} cdot frac{dt}{dx} = frac{dy}{dx} = frac{i(1+mu)}{1-mu}$$?
– Mattos
Nov 22 at 1:55
Yes, I realized the chain rule here, after posting the question. So I think I understand that such a $y$ exists because $i(1+mu)/(1-mu)$ is something that can be integrated.
– user135520
Nov 22 at 2:05
add a comment |
up vote
1
down vote
favorite
up vote
1
down vote
favorite
I am reading a proof of the measurable mapping theorem which shows the existence of a solution to the Beltrami equation in the simple case when $mu in L^{infty}(mathbb{C})$ is real analytic (due to Gauss)
begin{equation}
(1-mu(x,y))frac{partial{f}}{partial{x}}+ i(1+mu(x,y)))frac{partial{f}}{partial{y}}=0
tag{4.5.8}
end{equation}
From what I understand, we are looking for a curve $(x(t), y(t))$ which satisfies
$$frac{dx}{dt}=1-mu(x,y)$$ and
$$frac{dy}{dt}=i(1+mu(x,y))$$.
The author then points out that such a curve would satisfy
$$frac{dy}{dx}= ifrac{1+u}{1-u} tag{*}$$
I wanted to understand how one goes from the system of ODE's above to (*). Does $mu$ being real analytic imply that there is a solution to the system above
Furthermore, if there is such a solution, the inverse function theorem tells us that the solution is a local homeomorphism, can we say anything about uniqueness just from the ODE theory?
pde teichmueller-theory
I am reading a proof of the measurable mapping theorem which shows the existence of a solution to the Beltrami equation in the simple case when $mu in L^{infty}(mathbb{C})$ is real analytic (due to Gauss)
begin{equation}
(1-mu(x,y))frac{partial{f}}{partial{x}}+ i(1+mu(x,y)))frac{partial{f}}{partial{y}}=0
tag{4.5.8}
end{equation}
From what I understand, we are looking for a curve $(x(t), y(t))$ which satisfies
$$frac{dx}{dt}=1-mu(x,y)$$ and
$$frac{dy}{dt}=i(1+mu(x,y))$$.
The author then points out that such a curve would satisfy
$$frac{dy}{dx}= ifrac{1+u}{1-u} tag{*}$$
I wanted to understand how one goes from the system of ODE's above to (*). Does $mu$ being real analytic imply that there is a solution to the system above
Furthermore, if there is such a solution, the inverse function theorem tells us that the solution is a local homeomorphism, can we say anything about uniqueness just from the ODE theory?
pde teichmueller-theory
pde teichmueller-theory
edited Nov 21 at 17:57
asked Nov 21 at 17:03
user135520
911718
911718
I suspect your third equation should read $dy/dt = i(1 + mu(x, y))$, not $dx/dt = i(1 + mu(x, y))$. Could I be right? Cheers!
– Robert Lewis
Nov 21 at 17:32
1
Yes! Thank you!
– user135520
Nov 21 at 17:57
Glad to help out, my friend!
– Robert Lewis
Nov 21 at 18:02
1
Are you asking how $$x' = 1 - mu, quad y' = i(1+mu) implies frac{y'}{x'} = frac{dy}{dt} cdot frac{dt}{dx} = frac{dy}{dx} = frac{i(1+mu)}{1-mu}$$?
– Mattos
Nov 22 at 1:55
Yes, I realized the chain rule here, after posting the question. So I think I understand that such a $y$ exists because $i(1+mu)/(1-mu)$ is something that can be integrated.
– user135520
Nov 22 at 2:05
add a comment |
I suspect your third equation should read $dy/dt = i(1 + mu(x, y))$, not $dx/dt = i(1 + mu(x, y))$. Could I be right? Cheers!
– Robert Lewis
Nov 21 at 17:32
1
Yes! Thank you!
– user135520
Nov 21 at 17:57
Glad to help out, my friend!
– Robert Lewis
Nov 21 at 18:02
1
Are you asking how $$x' = 1 - mu, quad y' = i(1+mu) implies frac{y'}{x'} = frac{dy}{dt} cdot frac{dt}{dx} = frac{dy}{dx} = frac{i(1+mu)}{1-mu}$$?
– Mattos
Nov 22 at 1:55
Yes, I realized the chain rule here, after posting the question. So I think I understand that such a $y$ exists because $i(1+mu)/(1-mu)$ is something that can be integrated.
– user135520
Nov 22 at 2:05
I suspect your third equation should read $dy/dt = i(1 + mu(x, y))$, not $dx/dt = i(1 + mu(x, y))$. Could I be right? Cheers!
– Robert Lewis
Nov 21 at 17:32
I suspect your third equation should read $dy/dt = i(1 + mu(x, y))$, not $dx/dt = i(1 + mu(x, y))$. Could I be right? Cheers!
– Robert Lewis
Nov 21 at 17:32
1
1
Yes! Thank you!
– user135520
Nov 21 at 17:57
Yes! Thank you!
– user135520
Nov 21 at 17:57
Glad to help out, my friend!
– Robert Lewis
Nov 21 at 18:02
Glad to help out, my friend!
– Robert Lewis
Nov 21 at 18:02
1
1
Are you asking how $$x' = 1 - mu, quad y' = i(1+mu) implies frac{y'}{x'} = frac{dy}{dt} cdot frac{dt}{dx} = frac{dy}{dx} = frac{i(1+mu)}{1-mu}$$?
– Mattos
Nov 22 at 1:55
Are you asking how $$x' = 1 - mu, quad y' = i(1+mu) implies frac{y'}{x'} = frac{dy}{dt} cdot frac{dt}{dx} = frac{dy}{dx} = frac{i(1+mu)}{1-mu}$$?
– Mattos
Nov 22 at 1:55
Yes, I realized the chain rule here, after posting the question. So I think I understand that such a $y$ exists because $i(1+mu)/(1-mu)$ is something that can be integrated.
– user135520
Nov 22 at 2:05
Yes, I realized the chain rule here, after posting the question. So I think I understand that such a $y$ exists because $i(1+mu)/(1-mu)$ is something that can be integrated.
– user135520
Nov 22 at 2:05
add a comment |
active
oldest
votes
active
oldest
votes
active
oldest
votes
active
oldest
votes
active
oldest
votes
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%2f3008023%2fmethod-of-characteristics-for-the-beltrami-equation-when-mu-is-real-analytic%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
I suspect your third equation should read $dy/dt = i(1 + mu(x, y))$, not $dx/dt = i(1 + mu(x, y))$. Could I be right? Cheers!
– Robert Lewis
Nov 21 at 17:32
1
Yes! Thank you!
– user135520
Nov 21 at 17:57
Glad to help out, my friend!
– Robert Lewis
Nov 21 at 18:02
1
Are you asking how $$x' = 1 - mu, quad y' = i(1+mu) implies frac{y'}{x'} = frac{dy}{dt} cdot frac{dt}{dx} = frac{dy}{dx} = frac{i(1+mu)}{1-mu}$$?
– Mattos
Nov 22 at 1:55
Yes, I realized the chain rule here, after posting the question. So I think I understand that such a $y$ exists because $i(1+mu)/(1-mu)$ is something that can be integrated.
– user135520
Nov 22 at 2:05