AW: Nichtlokalität in der Loop QGT
Zitat:
Zitat von Bernhard
Darüberhinaus bin ich mir nicht sicher, ob der Satz so in der vollen Allgemeingültigkeit stimmt.
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Doch, das stimmt:
https://en.wikipedia.org/wiki/Spin_structure
... necessary and sufficient conditions for the existence of a spin structure on an oriented Riemannian manifold (M,g). The obstruction to having a spin structure is a certain element [k] ... the second Stiefel–Whitney class ...
Sie auch hier:
https://mathoverflow.net/questions/8...spin-manifolds
A surface is orientable if and only if it contains no Moebius bands -- a regular neighbourhood of any simple closed curve must be a cylinder ... a surface admits a spin structure if and only if it is orientable.
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Niels Bohr brainwashed a whole generation of theorists into thinking that the job (interpreting quantum theory) was done 50 years ago.
Ge?ndert von TomS (19.04.19 um 18:08 Uhr)
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