Undergrad The uniqueness of D=4

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The discussion explores the uniqueness of four-dimensional spacetime, highlighting early contributions from Weyl, Ehrenfest, and Whitrow, and noting the significance of Tangherlini's work on Schwarzschild metrics. It raises questions about relevant literature and how modern theories address Ehrenfest's arguments regarding dimensionality. The concept of "extra dimensions" being microscopic is proposed as a possible explanation for higher dimensionality. The mathematical implications of compactifications and their stability are also considered. Overall, the conversation emphasizes the complexity and ongoing exploration of dimensionality in theoretical physics.
arivero
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Discussions about having 3 spacial dimensions
I have found an interesting rabbit hole, because I thought the question of why we live in 3+1 was mainly a matter of footnotes and off-press debates. But it seems if was touched early by Weyl, Ehrenfest and Whitrow

https://einsteinpapers.press.princeton.edu/vol13-doc/764
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And then elaborated for Schwarzchild metrics by Tangherlini, who seems to be the root citation nowadays.

Is there any other relevant literature? What have you read on the topic? How does modern theory evade Eherenfest's arguments?
 

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For higher dimensionality, it seems to me that one way is to have “extra dimensions” be microscopic.
 
robphy said:
For higher dimensionality, it seems to me that one way is to have “extra dimensions” be microscopic.
That is empirically, of course. But point is, mathematically? with extra dimensions the argument does not disappear; it has some extra discussion about what compactifcations are stable. The point of D=7+4...
 
A good one to everyone. My previous post on this subject here on the forum was a fiasco. I’d like to apologize to everyone who did their best to comment and got ignored by me. In defence, I could tell you I had really little time to spend on discussion, and just overlooked the explanations that seemed irrelevant (why they seemed irrelevant, I will tell you at the end of this). Before we get to the point, I will kindly ask you to comment having considered this text carefully, because...