PAllen's latest activity

I don't believe this is correct, and you haven't made any attempt to demonstrate this part. The calculation for such an annulus with...

I think the implication is a similar phenomenon - the circumference of the rim grow unbounded, but this leads only to limiting area of 2...

So, if you do just treat the rim as one dimensional, with a linear mass distribution per the COM frame, you do get KE unbounded in the...

Qualitatively, what I am getting at is that as the rim speed approaches c, the number of small area elements of given measure (per a...

I think the cause is that the mass distribution is specified in the inertial frame. Then, in the local frame of a rotating piece, as the...

Getting back to the original question, rephrased as: can the intrinsic geometry of a topologically trivial piece of a general Lorentzian...

To me, the idea is that formalizing the notion of global isotropy and homogeneity leads to both topological constraints and geometric...

It seems to me that global homogeneity and isotropy, formalized as requiring the product of R and a maximally symmetric, homeneous...

I have bumped into problems that are trivial given the assumption that there is a well defined answer, but more tedious if you don't...

In general, no. We can choose any coordinate system we please according to whatever amuses us, and there's no reason that the...

Of course you can look at it either way. Another statement is that Minkowski spacetime is the analytic continuation of the geodesically...

Also, in the other thread you thread, you said "No, that's not Minkowski coordinates, that's Milne coordinates. You can't put the...

I think you are missing my point. We start with just topology, no metric. The topology we start will is all of ##R^4##. In one case, we...

Correct. It’s occurs to me that there is another way to look at this that strongly justifies treating the Milne spacetime as a...

[Moderator's note: Spin-off from another thread due to question change. Edited to remove content specific to the other thread.] You can...