PAllen's latest activity

Ok, if we're bringing this back, I'll share my results. In reference to the diagram in the original post, let c be the segment labeled...

So, FW transport along any curve will preserve all of these properties. Parallel transport will only preserve them along a geodesic. For...

But that operation is typically called the exponential map (and is a completely rigorous construct)...

That is an exceedingly narrow statement of the equivalence principle. The most commonly accepted meaning of strong equivalence principle...

That's not an update. It shares exactly one author, and the topic is not the same. Obviously, there is some relationship, but that's...

I wondered if anyone had ever treated voids using numerical relativity rather than more indirect approximations. I came across the...

While the FLRW metric, when used for a realistic universe, is purely an emergent approximation at large scales, there is one aspect of...

Yeah, but if you are talking about galaxies, you are outside the FLRW idealized model - that has only perfect fluid with different...

As far as I know, the common models of quintessence still use the FLRW equation metric, just with particular forms of ##a(t)##. In...

One thought that occurs to me is that virtually all learning is self-learning. If you enroll in a course and listen to the lectures but...

I don’t think the difficulty is insurmountable. I have a counterexample from my own experience. I wanted to learn calculus before the...

I like it and will probably play with it some. I'll ask if I have any questions. I appreciate your effort. I disagree with the decision...

No, because its total surface area is finite. It is actually just a small piece of the hyperbolic plane, it just 'looks' big in...

I can’t seem to let this go, partly because some have asked for how to make the embedding result (part of Euclidean plane in 3-sphere)...

I don't know if I can track it down from a long ago posts of mine, but I discussed a paper by a mathematician specializing GR that...