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Tagged with algebraic-topology differential-geometry
3
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Reidemeister Torsion
Can somebody in a layman's language explain what is a Reidemeister Torsion? This seems to play an important role in path integral of 2+1-gravity as demonstrated here in arXiv:gr-qc/9406006. This is ...
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Which geometry does not allow the existence of matter?
I have seen these lectures by Fredric Schuller that discuss the obstruction theory and the role of global geometric properties in admitting a spin structure.
See the video at 01:27:52
https://youtu....
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Simple explanation for what a torsor is
I am studying Chris Elliott's notes on Line and Surface Operators in Gauge Theories (available here).
In the notes, there's a mention of the fact that (for $G = U(1)$),
$$W_{\gamma, n}(A) = e^{in\...
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