Differential geometry MOC

Tangent bundle

Let 𝑀 be a 𝐢𝛼-manifold. The tangent bundle is a vector bundle of all the tangent spaces of 𝑀, diff so as a set

𝑇𝑀=βˆπ‘βˆˆπ‘€π‘‡π‘π‘€=β‹ƒπ‘βˆˆπ‘€{𝑝}×𝑇𝑝𝑀.

The construction of topological and 𝐢𝛼-structure is a little more involved. Let π’œ be the maximal atlas for 𝑀, so each (π‘₯,π‘ˆ) βˆˆπ’œ gives a 𝐢𝛼-isomorphism

π‘₯:π‘ˆβ†’β„π‘›

which induces a bijection

˜π‘₯:πœ‹βˆ’1π‘ˆβ†’β„π‘›Γ—β„π‘›(𝑝,π‘£πœ‡πœ•πœ‡)↦(π‘₯(𝑝),(π‘£πœ‡))

which induce an atlas on 𝑇𝑀. Thus 𝐴 βŠ†π‘‡π‘€ is open iff ˜π‘₯(𝐴 βˆ©πœ‹βˆ’1π‘ˆ) is open for every (π‘₯,π‘ˆ) βˆˆπ’œ.


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