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MalbertKerman | 7 months ago

The jump from spherical harmonics to eigenfunctions on a general mesh, and the specific example mesh chosen, might be the finest mathematical joke I've seen this decade.

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gsf_emergency_2|7 months ago

Related to this footnote in TFA?

>If you’re alarmed by the fact that the set of all real functions does not form a HILBERT SPACE, you’re probably not in the target audience of this post."

Video: https://youtu.be/q8gng_2gn70?t=8m3s

Thanks to

https://news.ycombinator.com/item?id=44481933

Y_Y|7 months ago

If you're wondering what a Hilbert space, know that you're in good company.

> Dr. von Neumann, ich möchte gerne wissen, was ist denn eigentlich ein Hilbertscher Raum? (Dr. von Neumann, I'd would really like to know, just what exactly is a Hilbert space?)

Asked to John von Neumann to David Hilbert at a lecture.

https://ncatlab.org/nlab/show/Hilbert+space#fn:1

I'd like to add, as a physicist by training, that anything can be a Hilbert space if you wish hard enough. You can even use results about countable vector spaces if you need them!

sixo|7 months ago

Would you explain the joke for the rest of us?

MalbertKerman|7 months ago

It's quietly reversing the traditional "We approximate the cow to be a sphere" and showing how the spherical math can, in fact, be generalized to solutions on the cow.

xeonmc|7 months ago

Spherical Haromics approximating Spherical Cows?