Skip to main content
corrected spelling in title
Source Link
R.P.
  • 4.7k
  • 19
  • 43
  • 67

Understanding the lieLie derivative by multivector fields

For a vector field $X$ on a manifold there are two ways to define a Lie derivative: an algebraic one using Cartan's formula $\mathcal{L}_X \alpha = i_X d \alpha + d i_X \alpha$ and a dynamical one using the flow $\phi^X_t$, $${\cal L}_X \alpha = \frac{d}{dt}\biggl|_{t=0} \left(\bigl(\Phi^t_X\bigr)^* T\right)$$

Given a multivector field $X$ one can define its Lie derivative by means of Cartan formula, i., $\mathcal{L}_X \alpha = i_X d \alpha + d i_X alpha$$\mathcal{L}_X \alpha = i_X d \alpha + d i_X \alpha$. See, for example [1].

My broad question is if the Lie derivative by a multivector means something dynamical. These are some fuzzy questions for which any help or reference would be welcomed.

  • In the simplest case, if $X = X_1\wedge \ldots \wedge X_n$ and the e_i span an integrable distribution, is $\alpha$ constant in some sense on the leaves of this distribution. What happens if the multivector is not integrable?

  • Is there a generalization of the concept of flow for a multivector that applies to this situation?

  • My current geometric understanding of general multivectors is that they are linear combinations of hyperplanes modulo the Plücker relations (whose geometric interpretation feels somewhat obscure to me). I would like to have a better interpretation. On question [2] on this site it is stated that they are global sections of a line bundle over the Grasmannian, some reference of this fact would be useful.

[1] W. M. Tulczyjew, «The Graded Lie Algebra of Multivector Fields and the Generalized Lie Derivative of Forms».

[2] Denis Serre (https://mathoverflow.net/users/8799/denis-serre), Grassmannian as a submanifold of $\Lambda^m(E)$., URL (version: 2011-11-14): Grassmannian as a submanifold of $\Lambda^m(E)$.

Understanding the lie derivative by multivector fields

For a vector field $X$ on a manifold there are two ways to define a Lie derivative: an algebraic one using Cartan's formula $\mathcal{L}_X \alpha = i_X d \alpha + d i_X \alpha$ and a dynamical one using the flow $\phi^X_t$, $${\cal L}_X \alpha = \frac{d}{dt}\biggl|_{t=0} \left(\bigl(\Phi^t_X\bigr)^* T\right)$$

Given a multivector field $X$ one can define its Lie derivative by means of Cartan formula, i., $\mathcal{L}_X \alpha = i_X d \alpha + d i_X alpha$. See, for example [1].

My broad question is if the Lie derivative by a multivector means something dynamical. These are some fuzzy questions for which any help or reference would be welcomed.

  • In the simplest case, if $X = X_1\wedge \ldots \wedge X_n$ and the e_i span an integrable distribution, is $\alpha$ constant in some sense on the leaves of this distribution. What happens if the multivector is not integrable?

  • Is there a generalization of the concept of flow for a multivector that applies to this situation?

  • My current geometric understanding of general multivectors is that they are linear combinations of hyperplanes modulo the Plücker relations (whose geometric interpretation feels somewhat obscure to me). I would like to have a better interpretation. On question [2] on this site it is stated that they are global sections of a line bundle over the Grasmannian, some reference of this fact would be useful.

[1] W. M. Tulczyjew, «The Graded Lie Algebra of Multivector Fields and the Generalized Lie Derivative of Forms».

[2] Denis Serre (https://mathoverflow.net/users/8799/denis-serre), Grassmannian as a submanifold of $\Lambda^m(E)$., URL (version: 2011-11-14): Grassmannian as a submanifold of $\Lambda^m(E)$.

Understanding the Lie derivative by multivector fields

For a vector field $X$ on a manifold there are two ways to define a Lie derivative: an algebraic one using Cartan's formula $\mathcal{L}_X \alpha = i_X d \alpha + d i_X \alpha$ and a dynamical one using the flow $\phi^X_t$, $${\cal L}_X \alpha = \frac{d}{dt}\biggl|_{t=0} \left(\bigl(\Phi^t_X\bigr)^* T\right)$$

Given a multivector field $X$ one can define its Lie derivative by means of Cartan formula, i., $\mathcal{L}_X \alpha = i_X d \alpha + d i_X \alpha$. See, for example [1].

My broad question is if the Lie derivative by a multivector means something dynamical. These are some fuzzy questions for which any help or reference would be welcomed.

  • In the simplest case, if $X = X_1\wedge \ldots \wedge X_n$ and the e_i span an integrable distribution, is $\alpha$ constant in some sense on the leaves of this distribution. What happens if the multivector is not integrable?

  • Is there a generalization of the concept of flow for a multivector that applies to this situation?

  • My current geometric understanding of general multivectors is that they are linear combinations of hyperplanes modulo the Plücker relations (whose geometric interpretation feels somewhat obscure to me). I would like to have a better interpretation. On question [2] on this site it is stated that they are global sections of a line bundle over the Grasmannian, some reference of this fact would be useful.

[1] W. M. Tulczyjew, «The Graded Lie Algebra of Multivector Fields and the Generalized Lie Derivative of Forms».

[2] Denis Serre (https://mathoverflow.net/users/8799/denis-serre), Grassmannian as a submanifold of $\Lambda^m(E)$., URL (version: 2011-11-14): Grassmannian as a submanifold of $\Lambda^m(E)$.

Source Link
mlainz
  • 161
  • 4

Understanding the lie derivarive by multivector fields

For a vector field $X$ on a manifold there are two ways to define a Lie derivative: an algebraic one using Cartan's formula $\mathcal{L}_X \alpha = i_X d \alpha + d i_X \alpha$ and a dynamical one using the flow $\phi^X_t$, $${\cal L}_X \alpha = \frac{d}{dt}\biggl|_{t=0} \left(\bigl(\Phi^t_X\bigr)^* T\right)$$

Given a multivector field $X$ one can define its Lie derivative by means of Cartan formula, i., $\mathcal{L}_X \alpha = i_X d \alpha + d i_X alpha$. See, for example [1].

My broad question is if the Lie derivative by a multivector means something dynamical. These are some fuzzy questions for which any help or reference would be welcomed.

  • In the simplest case, if $X = X_1\wedge \ldots \wedge X_n$ and the e_i span an integrable distribution, is $\alpha$ constant in some sense on the leaves of this distribution. What happens if the multivector is not integrable?

  • Is there a generalization of the concept of flow for a multivector that applies to this situation?

  • My current geometric understanding of general multivectors is that they are linear combinations of hyperplanes modulo the Plücker relations (whose geometric interpretation feels somewhat obscure to me). I would like to have a better interpretation. On question [2] on this site it is stated that they are global sections of a line bundle over the Grasmannian, some reference of this fact would be useful.

[1] W. M. Tulczyjew, «The Graded Lie Algebra of Multivector Fields and the Generalized Lie Derivative of Forms».

[2] Denis Serre (https://mathoverflow.net/users/8799/denis-serre), Grassmannian as a submanifold of $\Lambda^m(E)$., URL (version: 2011-11-14): Grassmannian as a submanifold of $\Lambda^m(E)$.