Worked examples of Lie derivatives
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I'm trying to find the Lie derivative of a 2-form $sin(theta)dtheta wedge dphi$ with respect to a vector field given in a differential basis $a partial/ partial phi$ and I think the way to go here is to use Cartan's formula but I'm not sure how to do that. I can't find any worked examples in any differential textbook or online, everything seems to focus on proving identities not performing actual calculations. Can somebody point me to a useful resource with some exercises or step-by-step examples?
differential-geometry differential-forms lie-derivative
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I'm trying to find the Lie derivative of a 2-form $sin(theta)dtheta wedge dphi$ with respect to a vector field given in a differential basis $a partial/ partial phi$ and I think the way to go here is to use Cartan's formula but I'm not sure how to do that. I can't find any worked examples in any differential textbook or online, everything seems to focus on proving identities not performing actual calculations. Can somebody point me to a useful resource with some exercises or step-by-step examples?
differential-geometry differential-forms lie-derivative
$endgroup$
add a comment |
$begingroup$
I'm trying to find the Lie derivative of a 2-form $sin(theta)dtheta wedge dphi$ with respect to a vector field given in a differential basis $a partial/ partial phi$ and I think the way to go here is to use Cartan's formula but I'm not sure how to do that. I can't find any worked examples in any differential textbook or online, everything seems to focus on proving identities not performing actual calculations. Can somebody point me to a useful resource with some exercises or step-by-step examples?
differential-geometry differential-forms lie-derivative
$endgroup$
I'm trying to find the Lie derivative of a 2-form $sin(theta)dtheta wedge dphi$ with respect to a vector field given in a differential basis $a partial/ partial phi$ and I think the way to go here is to use Cartan's formula but I'm not sure how to do that. I can't find any worked examples in any differential textbook or online, everything seems to focus on proving identities not performing actual calculations. Can somebody point me to a useful resource with some exercises or step-by-step examples?
differential-geometry differential-forms lie-derivative
differential-geometry differential-forms lie-derivative
edited Jan 21 at 6:17


Ivo Terek
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46.3k954142
asked Jan 20 at 23:10
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I understand that you want to compute $$mathcal{L}_{a partial_theta}(sintheta,{rm d}thetawedge {rm d}phi).$$In this case it is easy enough to use the definition via flows. The flow of the vector field $apartial_theta$ is just $$Phi_{t,apartial_theta}(theta,phi) = (theta+at, phi),$$so $$begin{align}mathcal{L}_{apartial_theta}(sintheta,{rm d}theta wedge {rm d}theta) &= frac{rm d}{{rm d}t}bigg|_{t=0} (Phi_{t,apartial_theta})^* (sintheta,{rm d}theta wedge {rm d}phi) \ &= frac{rm d}{{rm d}t}bigg|_{t=0} sin(theta+at),{rm d}(theta+at)wedge{rm d}phi \ &= frac{{rm d}}{{rm d}t}bigg|_{t=0} sin(theta+at),{rm d}thetawedge {rm d}phi \ &= acos(theta+at)bigg|_{t=0},{rm d}thetawedge{rm d}phi \ &= a costheta,{rm d}thetawedge{rm d}phi.end{align}$$If you want to double-check using Cartan's Homotopy Formula $mathcal{L}_{apartial_theta} = iota_{apartial_theta}circ {rm d}+{rm d}circ iota_{apartial_theta}$, you can just use that $${rm d}(sintheta,{rm d}thetawedge {rm d}phi) = costheta ,{rm d}thetawedge{rm d}thetawedge {rm d}phi = 0$$because ${rm d}theta$ repeats, and compute $$begin{align} iota_{apartial_theta}(sintheta,{rm d}thetawedge{rm d}phi) &= sintheta,({rm d}theta wedge {rm d}phi)(apartial_theta, cdot) \ &= sintheta begin{vmatrix} {rm d}theta(apartial_theta) & {rm d}theta \ {rm d}phi(apartial_theta) & {rm d}phiend{vmatrix} \ &= sin theta begin{vmatrix} a & {rm d}theta \ 0 & {rm d}phiend{vmatrix} \ &= a sin {rm d}phi,end{align}$$leading again to $$mathcal{L}_{apartial_theta} = {rm d}(asintheta,{rm d}phi) = acostheta,{rm d}theta wedge {rm d}phi.$$Anyway, you can look for more examples like this in the book Analysis and Algebra in Differentiable Manifolds -
A Workbook for Students and Teachers by Gadea, et al.
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$L_X=i_Xd+di_X$, you have $d(sin(theta)dthetawedge dphi)=cos(theta)dthetawedge dthetawedge dphi=0$
Let $(u,v)$ be a vector of $T_{theta,phi}mathbb{R}^2$ $i_{a{partial}over{partialphi}}sin(theta)dthetawedge dphi=sin(theta)detpmatrix{0&ucr a&v}=-asin(theta)u=-asin(theta)dtheta(u,v)$. This implies that $d(i_{a{partial}over{partialphi}}sin(theta)dthetawedge dphi)=0$
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I understand that you want to compute $$mathcal{L}_{a partial_theta}(sintheta,{rm d}thetawedge {rm d}phi).$$In this case it is easy enough to use the definition via flows. The flow of the vector field $apartial_theta$ is just $$Phi_{t,apartial_theta}(theta,phi) = (theta+at, phi),$$so $$begin{align}mathcal{L}_{apartial_theta}(sintheta,{rm d}theta wedge {rm d}theta) &= frac{rm d}{{rm d}t}bigg|_{t=0} (Phi_{t,apartial_theta})^* (sintheta,{rm d}theta wedge {rm d}phi) \ &= frac{rm d}{{rm d}t}bigg|_{t=0} sin(theta+at),{rm d}(theta+at)wedge{rm d}phi \ &= frac{{rm d}}{{rm d}t}bigg|_{t=0} sin(theta+at),{rm d}thetawedge {rm d}phi \ &= acos(theta+at)bigg|_{t=0},{rm d}thetawedge{rm d}phi \ &= a costheta,{rm d}thetawedge{rm d}phi.end{align}$$If you want to double-check using Cartan's Homotopy Formula $mathcal{L}_{apartial_theta} = iota_{apartial_theta}circ {rm d}+{rm d}circ iota_{apartial_theta}$, you can just use that $${rm d}(sintheta,{rm d}thetawedge {rm d}phi) = costheta ,{rm d}thetawedge{rm d}thetawedge {rm d}phi = 0$$because ${rm d}theta$ repeats, and compute $$begin{align} iota_{apartial_theta}(sintheta,{rm d}thetawedge{rm d}phi) &= sintheta,({rm d}theta wedge {rm d}phi)(apartial_theta, cdot) \ &= sintheta begin{vmatrix} {rm d}theta(apartial_theta) & {rm d}theta \ {rm d}phi(apartial_theta) & {rm d}phiend{vmatrix} \ &= sin theta begin{vmatrix} a & {rm d}theta \ 0 & {rm d}phiend{vmatrix} \ &= a sin {rm d}phi,end{align}$$leading again to $$mathcal{L}_{apartial_theta} = {rm d}(asintheta,{rm d}phi) = acostheta,{rm d}theta wedge {rm d}phi.$$Anyway, you can look for more examples like this in the book Analysis and Algebra in Differentiable Manifolds -
A Workbook for Students and Teachers by Gadea, et al.
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I understand that you want to compute $$mathcal{L}_{a partial_theta}(sintheta,{rm d}thetawedge {rm d}phi).$$In this case it is easy enough to use the definition via flows. The flow of the vector field $apartial_theta$ is just $$Phi_{t,apartial_theta}(theta,phi) = (theta+at, phi),$$so $$begin{align}mathcal{L}_{apartial_theta}(sintheta,{rm d}theta wedge {rm d}theta) &= frac{rm d}{{rm d}t}bigg|_{t=0} (Phi_{t,apartial_theta})^* (sintheta,{rm d}theta wedge {rm d}phi) \ &= frac{rm d}{{rm d}t}bigg|_{t=0} sin(theta+at),{rm d}(theta+at)wedge{rm d}phi \ &= frac{{rm d}}{{rm d}t}bigg|_{t=0} sin(theta+at),{rm d}thetawedge {rm d}phi \ &= acos(theta+at)bigg|_{t=0},{rm d}thetawedge{rm d}phi \ &= a costheta,{rm d}thetawedge{rm d}phi.end{align}$$If you want to double-check using Cartan's Homotopy Formula $mathcal{L}_{apartial_theta} = iota_{apartial_theta}circ {rm d}+{rm d}circ iota_{apartial_theta}$, you can just use that $${rm d}(sintheta,{rm d}thetawedge {rm d}phi) = costheta ,{rm d}thetawedge{rm d}thetawedge {rm d}phi = 0$$because ${rm d}theta$ repeats, and compute $$begin{align} iota_{apartial_theta}(sintheta,{rm d}thetawedge{rm d}phi) &= sintheta,({rm d}theta wedge {rm d}phi)(apartial_theta, cdot) \ &= sintheta begin{vmatrix} {rm d}theta(apartial_theta) & {rm d}theta \ {rm d}phi(apartial_theta) & {rm d}phiend{vmatrix} \ &= sin theta begin{vmatrix} a & {rm d}theta \ 0 & {rm d}phiend{vmatrix} \ &= a sin {rm d}phi,end{align}$$leading again to $$mathcal{L}_{apartial_theta} = {rm d}(asintheta,{rm d}phi) = acostheta,{rm d}theta wedge {rm d}phi.$$Anyway, you can look for more examples like this in the book Analysis and Algebra in Differentiable Manifolds -
A Workbook for Students and Teachers by Gadea, et al.
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I understand that you want to compute $$mathcal{L}_{a partial_theta}(sintheta,{rm d}thetawedge {rm d}phi).$$In this case it is easy enough to use the definition via flows. The flow of the vector field $apartial_theta$ is just $$Phi_{t,apartial_theta}(theta,phi) = (theta+at, phi),$$so $$begin{align}mathcal{L}_{apartial_theta}(sintheta,{rm d}theta wedge {rm d}theta) &= frac{rm d}{{rm d}t}bigg|_{t=0} (Phi_{t,apartial_theta})^* (sintheta,{rm d}theta wedge {rm d}phi) \ &= frac{rm d}{{rm d}t}bigg|_{t=0} sin(theta+at),{rm d}(theta+at)wedge{rm d}phi \ &= frac{{rm d}}{{rm d}t}bigg|_{t=0} sin(theta+at),{rm d}thetawedge {rm d}phi \ &= acos(theta+at)bigg|_{t=0},{rm d}thetawedge{rm d}phi \ &= a costheta,{rm d}thetawedge{rm d}phi.end{align}$$If you want to double-check using Cartan's Homotopy Formula $mathcal{L}_{apartial_theta} = iota_{apartial_theta}circ {rm d}+{rm d}circ iota_{apartial_theta}$, you can just use that $${rm d}(sintheta,{rm d}thetawedge {rm d}phi) = costheta ,{rm d}thetawedge{rm d}thetawedge {rm d}phi = 0$$because ${rm d}theta$ repeats, and compute $$begin{align} iota_{apartial_theta}(sintheta,{rm d}thetawedge{rm d}phi) &= sintheta,({rm d}theta wedge {rm d}phi)(apartial_theta, cdot) \ &= sintheta begin{vmatrix} {rm d}theta(apartial_theta) & {rm d}theta \ {rm d}phi(apartial_theta) & {rm d}phiend{vmatrix} \ &= sin theta begin{vmatrix} a & {rm d}theta \ 0 & {rm d}phiend{vmatrix} \ &= a sin {rm d}phi,end{align}$$leading again to $$mathcal{L}_{apartial_theta} = {rm d}(asintheta,{rm d}phi) = acostheta,{rm d}theta wedge {rm d}phi.$$Anyway, you can look for more examples like this in the book Analysis and Algebra in Differentiable Manifolds -
A Workbook for Students and Teachers by Gadea, et al.
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I understand that you want to compute $$mathcal{L}_{a partial_theta}(sintheta,{rm d}thetawedge {rm d}phi).$$In this case it is easy enough to use the definition via flows. The flow of the vector field $apartial_theta$ is just $$Phi_{t,apartial_theta}(theta,phi) = (theta+at, phi),$$so $$begin{align}mathcal{L}_{apartial_theta}(sintheta,{rm d}theta wedge {rm d}theta) &= frac{rm d}{{rm d}t}bigg|_{t=0} (Phi_{t,apartial_theta})^* (sintheta,{rm d}theta wedge {rm d}phi) \ &= frac{rm d}{{rm d}t}bigg|_{t=0} sin(theta+at),{rm d}(theta+at)wedge{rm d}phi \ &= frac{{rm d}}{{rm d}t}bigg|_{t=0} sin(theta+at),{rm d}thetawedge {rm d}phi \ &= acos(theta+at)bigg|_{t=0},{rm d}thetawedge{rm d}phi \ &= a costheta,{rm d}thetawedge{rm d}phi.end{align}$$If you want to double-check using Cartan's Homotopy Formula $mathcal{L}_{apartial_theta} = iota_{apartial_theta}circ {rm d}+{rm d}circ iota_{apartial_theta}$, you can just use that $${rm d}(sintheta,{rm d}thetawedge {rm d}phi) = costheta ,{rm d}thetawedge{rm d}thetawedge {rm d}phi = 0$$because ${rm d}theta$ repeats, and compute $$begin{align} iota_{apartial_theta}(sintheta,{rm d}thetawedge{rm d}phi) &= sintheta,({rm d}theta wedge {rm d}phi)(apartial_theta, cdot) \ &= sintheta begin{vmatrix} {rm d}theta(apartial_theta) & {rm d}theta \ {rm d}phi(apartial_theta) & {rm d}phiend{vmatrix} \ &= sin theta begin{vmatrix} a & {rm d}theta \ 0 & {rm d}phiend{vmatrix} \ &= a sin {rm d}phi,end{align}$$leading again to $$mathcal{L}_{apartial_theta} = {rm d}(asintheta,{rm d}phi) = acostheta,{rm d}theta wedge {rm d}phi.$$Anyway, you can look for more examples like this in the book Analysis and Algebra in Differentiable Manifolds -
A Workbook for Students and Teachers by Gadea, et al.
answered Jan 21 at 6:15


Ivo TerekIvo Terek
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$begingroup$
$L_X=i_Xd+di_X$, you have $d(sin(theta)dthetawedge dphi)=cos(theta)dthetawedge dthetawedge dphi=0$
Let $(u,v)$ be a vector of $T_{theta,phi}mathbb{R}^2$ $i_{a{partial}over{partialphi}}sin(theta)dthetawedge dphi=sin(theta)detpmatrix{0&ucr a&v}=-asin(theta)u=-asin(theta)dtheta(u,v)$. This implies that $d(i_{a{partial}over{partialphi}}sin(theta)dthetawedge dphi)=0$
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$L_X=i_Xd+di_X$, you have $d(sin(theta)dthetawedge dphi)=cos(theta)dthetawedge dthetawedge dphi=0$
Let $(u,v)$ be a vector of $T_{theta,phi}mathbb{R}^2$ $i_{a{partial}over{partialphi}}sin(theta)dthetawedge dphi=sin(theta)detpmatrix{0&ucr a&v}=-asin(theta)u=-asin(theta)dtheta(u,v)$. This implies that $d(i_{a{partial}over{partialphi}}sin(theta)dthetawedge dphi)=0$
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$begingroup$
$L_X=i_Xd+di_X$, you have $d(sin(theta)dthetawedge dphi)=cos(theta)dthetawedge dthetawedge dphi=0$
Let $(u,v)$ be a vector of $T_{theta,phi}mathbb{R}^2$ $i_{a{partial}over{partialphi}}sin(theta)dthetawedge dphi=sin(theta)detpmatrix{0&ucr a&v}=-asin(theta)u=-asin(theta)dtheta(u,v)$. This implies that $d(i_{a{partial}over{partialphi}}sin(theta)dthetawedge dphi)=0$
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$L_X=i_Xd+di_X$, you have $d(sin(theta)dthetawedge dphi)=cos(theta)dthetawedge dthetawedge dphi=0$
Let $(u,v)$ be a vector of $T_{theta,phi}mathbb{R}^2$ $i_{a{partial}over{partialphi}}sin(theta)dthetawedge dphi=sin(theta)detpmatrix{0&ucr a&v}=-asin(theta)u=-asin(theta)dtheta(u,v)$. This implies that $d(i_{a{partial}over{partialphi}}sin(theta)dthetawedge dphi)=0$
edited Jan 20 at 23:58
answered Jan 20 at 23:21


Tsemo AristideTsemo Aristide
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