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Tuesday, 2015 December 29, 12:17 — me!me!me!

allonymy

A notice to renew my domain registration prompts thoughts of what I might have used instead: ansher, anwood, tonsher, tonwood ?

tonsher reminds me of an acquaintance whose bald spot looks uncannily like a monk’s tonsure — and that’s even funnier on a Jew. My own bald spot is not so sharply defined.

Sunday, 2015 June 7, 07:52 — mathematics, me!me!me!

logarithmic birthday

I’m exp(4) years old!

Monday, 2015 January 26, 21:51 — mathematics, merch

elusive avoidance

I’ve been designing printable models of the Lawson-Klein surface

w = cos(u) cos(2v)
x = cos(u) sin(2v)
y = sin(u) cos(v)
z = sin(u) sin(v)

As you can plainly see, this figure lives in S3 (positively curved 3-space), so stereographic projection can bring it into E3 (Euclidean 3-space) without adding more self-intersections. (It crosses itself at u=nπ.)

To minimize the distortion of the projection, I want the projection center to be as far as possible from the surface. One thing I tried was pursuit: starting with an arbitrary point P in S3 and an arbitrary point L(u,v) in the surface, move (u,v) to bring L closer to P while simultaneously moving P away from L. This gets me nowhere so far: either it fails to converge or P converges to the antipodes of L, which is also in the surface (change u by π).

Monday, 2014 November 24, 09:59 — me!me!me!, medicine

hidden dragon

For years I’ve occasionally had a mysterious itch at my lowest left rib, nothing showing on the skin. Now it has spread rightward at the same altitude, making me think: could this be mild shingles?

Saturday, 2014 June 7, 13:46 — mathematics, merch

unapologetically one-sided

My newest design on Shapeways is a model of the Lawson-Klein surface : a stereographic projection of

( cos(u)cos(2v), cos(u)sin(2v), sin(u)cos(v), sin(u)sin(v) )

Saturday, 2014 May 17, 22:33 — me!me!me!

oddly tempting

I hadn’t noticed before that my webhost offers MediaWiki. Some of the things I write here are not news, really, but things that sorta belong in my permanent exhibition but are too wordy for that page.