The letter ℘: name and origin? (2017)

I left college with a math degree and a profound antipathy for weird cursive symbols. The one that nearly killed me was the Greek "xi". I couldn't pronounce it, and I couldn't write it with any fluency, and in some of the classes I took it was everywhere.

Despite only having a CS degree, I was always especially fond of ξ due to its distinctiveness (and also didn’t have trouble writing or pronouncing it), moreso than letters like ν or ι, which are too close to v or i/j visually for my taste.

I encounter ξ (xi), and also ζ (zeta) a lot. Honestly, when I write them out by hand, I just make a "wild squiggly line" for ξ and a "simplified squiggly line" for ζ.

If I write it out by hand, it's most likely just for my eyes anyway, and I'd type it out on a computer if I'd want others to have a look at it. But even if I gave someone else my handwritten note, I think from context it would be pretty clear what the "squiggly lines" are supposed to be.

I think iota is fine because it's missing the dot that an i has, but nu is terrible, yeah. In fact, in some fonts nu is exactly v: https://en.wikipedia.org/wiki/Nu_(letter)

But then a lot of capital greek letters at least are identical to latin letters in those fonts, so I guess you have to choose carefully anyway... and pick the proper font/handwriting if you absolutely have to use nu. (Hopefully you don't.)

ζ is essentially a cursive z. ξ is near enough to a backwards 3.

ξ is literally three horizontal bars underneath each other, in cursive.

Indeed. Try to write Ξ sloppily using connected strokes and you'll end up with something vaguely like ξ.

> ξ is literally three horizontal bars underneath each other, in cursive.

And? So is 3.

I actually find xi easy to write, whereas zeta is really hard for me. I think the middle loop of the xi provides an anchor for what I'm aiming for, but zeta ends up as a nondescript squiggle. Sometimes I can't even properly picture what zeta looks like in my head. Is it like a 2, a 5, an S, or a Z? Or a cursive C or an italic G? It's all undifferentiated in my head.

I do still remember the day our math professor taught us both symbols. He did it very purposefully, like he knew it was all riding on him, and we'd all be lost if he didn't pass the arcane knowledge down.

There is a famous anecdote [0] about Barry Mazur coming up with the worst notation possible at a seminar talk in order to annoy Serge Lang. Mazur defined Ξ to be a complex number and considered the quotient of the conjugate of Ξ and Ξ. (Click link to view 8 lines on top of each other)

[0] https://mathoverflow.net/questions/18593/what-are-the-worst-...

The unstated point is to explain the connection between lowercase ξ and uppercase Ξ.

Paul Vojta p546 http://www.ams.org/notices/200605/fea-lang.pdf

When I was an undergraduate typing it out on a computer wasn’t an option, not with the hardware available at my school. It was handwritten, or nothing.

You guys do know that Greek speakers write those by hand all the time, right? It’s really not that difficult…

"All the time", yeah. Relatively to that, I have to write individual greek characters very rarely, as they are not part of my usual script. Almost never, compared to a greek person.

The same applies to the scripts used by e.g. Chinese, Arabian, and Korean speakers.

So naturally I am not a "fluent" writer of ξ and ζ, and since I virtually always write those characters in isolation instead of as part of words, it's a different mode of practice even when I do use them.

It's the same on the keyboard, by the way. My keyboard does not have ξ or ζ keys, it's all special.