Can Structure Constants Define a Metric in a 10D Lie Algebra?

Click For Summary
A 10-dimensional Lie algebra can utilize structure constants to potentially define a metric, particularly through the Killing-Cartan Form, which is non-degenerate for semi-simple algebras. The discussion highlights the importance of whether the Killing form is non-degenerate, as this indicates the semisimplicity of the Lie algebra. While the Killing form can be used to define metrics on root spaces, the conversation suggests caution in labeling it a metric on the structure constants themselves. The focus remains on the mathematical properties of the algebra rather than the specific field of functions used. Overall, the relationship between structure constants and metric formation in Lie algebras is complex and contingent on the algebra's characteristics.
jfy4
Messages
645
Reaction score
3
Hi,

Let's say I have a 10 dimensional Lie algebra over some field of functions, something along the lines of at least twice differentiable with twice differentiable inverses. The structure constants have inputs from this field. Is it possible to build a metric from these structure constants?

I have seen that a symmetric bi-linear form (the Killing-Cartan Form) that can also be non-degenerate for semi-simple algebras can be formed through contraction of the structure constants \kappa f^{\alpha\beta}_{\quad\gamma} f^{\delta\gamma}_{\quad\beta}=K^{\alpha\delta}. Are there any other contractions or tensors one can form from structure constants over a field of functions (something other than \mathbb{R} or \mathbb{C})?

Thanks,
 
Physics news on Phys.org
The field doesn't matter. What matters is, whether the Killing form is non degenerate or not, i.e. whether the Lie algebra is semisimple or not. I won't call the Killing form a metric on the structure constants, or any other attempt to define a metric on this finite set: Why? The Killing form defines a metric on the root spaces.
See: https://www.physicsforums.com/insights/lie-algebras-a-walkthrough-the-basics/
 
I am studying the mathematical formalism behind non-commutative geometry approach to quantum gravity. I was reading about Hopf algebras and their Drinfeld twist with a specific example of the Moyal-Weyl twist defined as F=exp(-iλ/2θ^(μν)∂_μ⊗∂_ν) where λ is a constant parametar and θ antisymmetric constant tensor. {∂_μ} is the basis of the tangent vector space over the underlying spacetime Now, from my understanding the enveloping algebra which appears in the definition of the Hopf algebra...

Similar threads

  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
Replies
4
Views
2K
  • · Replies 3 ·
Replies
3
Views
4K
  • · Replies 4 ·
Replies
4
Views
3K
Replies
2
Views
5K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 3 ·
Replies
3
Views
7K
  • · Replies 1 ·
Replies
1
Views
3K