What is the Role of Lie Groups in Isometry Actions on Spaces?

In summary, the group G acts by isometries on a space X, and the language used is not clear to the speaker. The speaker is unsure if they need to show that the action preserves distance, and asks for clarification. Another person mentions that if X is a Riemannian manifold, the differential of the action should preserve the metric tensor. The speaker then mentions that they are only told about a linear group acting on S^3 and there is a question about geodesics, suggesting that it may indeed be a Riemannian manifold.
  • #1
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Hi, everyone:

I am asked to show that a group G acts by isometries on a space X.

I am not clear about the languange, does anyone know what this means?.

Do I need to show that the action preserves distance, i.e, that

d(x,y)=d(gx,gy)?.

Thanks.
 
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  • #2
Depends on context, but if it is a Riemannian manifold, presumably you want to show that the differential of the action preserves the metric tensor.
 
  • #3
Thanks. I am only told of a linear group, i.e, a group of matrices
acting on S^3. There is a question on geodesics, so you may
be right, and we may need to consider this as a Riemannian mfld.
 

1. What are Lie groups?

Lie groups are mathematical objects that are used to study continuous symmetry. They are groups that have both a smooth manifold structure and a group structure, making them useful in many areas of mathematics and physics.

2. How are Lie groups different from other groups?

Lie groups are different from other groups because they have a smooth manifold structure, which means they are continuously differentiable and can be described by smooth functions. This allows for more advanced mathematical analysis and applications in physics.

3. What are some real-world applications of Lie groups?

Lie groups have many real-world applications, particularly in physics and engineering. They are used to study the symmetries of physical systems, such as in quantum mechanics and relativity. They are also used in robotics and computer graphics for motion planning and control.

4. What is the relationship between Lie groups and Lie algebras?

Lie groups and Lie algebras are closely related mathematical objects. Every Lie group has an associated Lie algebra, which is a vector space that captures the infinitesimal information about the group's structure. In turn, Lie algebras can be used to classify and study Lie groups.

5. Are there different types of Lie groups?

Yes, there are different types of Lie groups, including compact and non-compact Lie groups, simple and non-simple Lie groups, and connected and non-connected Lie groups. These types have different properties and applications, and they are classified based on their structure and symmetries.

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