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1 answer
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Is the manifold of complex points of a quotient of compact groups just the tangent bundle?

In great generality a Lie group mod its maximal compact subgroup is contractible (for example this is true for all connected Lie groups). Whenever this is true then the Lie group $ D $ is ...
Ian Gershon Teixeira's user avatar
12 votes
3 answers
3k views

Non-Lie Subgroups

A result of Borel and Lichnerowicz states that the holonomy group of a connection on a principal $G$-bundle is a Lie subgroup of $G$ (Cartan had earlier asserted this, but apparently without proof). ...
Harold Williams's user avatar
8 votes
1 answer
599 views

Exact condition for smooth homogeneous to imply Riemannian homogeneous for compact manifolds

Let $ (M,g) $ be a homogeneous Riemannian manifold. That is, the isometry group $ Iso(M,g) $ acts transitively on $ M $. Let $ \pi_1(M) $ be the fundamental group of $ M $. Then $ \pi_1(M) $ has ...
Ian Gershon Teixeira's user avatar
5 votes
0 answers
135 views

Specify the embedding of Lie groups (via the representation map) precisely as the embedding of two differentiable manifolds

How do we specify the embedding of a Lie group $G_1$ as a subgroup into a larger Lie group $G_2$, with $G_1 \subset G_2$ that agree with a constraint on the mapping between their representations? By ...
wonderich's user avatar
  • 10.5k
4 votes
1 answer
236 views

Submanifold of a Lie group whose tangent bundle is invariant under group (left) action

Edit: According to the interesting comment of Tobias Fritz we revise the question. Assume that $G$ is a Lie group and $M\subseteq G$ is a closed connected smooth submanifold of $G$ containing the ...
Ali Taghavi's user avatar
3 votes
2 answers
2k views

Is a manifold paracompact? Should it be?

We will say that a Hausdorff topological space $X$ is a smooth manifold if there is an open cover $(U_{\alpha})$ of $X$ and a corresponding collection of homeomorphisms $\varphi_{\alpha} : U_{\alpha} \...
AmorFati's user avatar
  • 1,379