Reminds me of a 360 (math blog) post where a prof used Xi as a variable and had an expression of the form Xi-over-Xi-bar:
see the 360 post here
http://threesixty360.wordpress.com/2008/10/31/happy-anniversary

At first I read xi-bar as xi-conjugate. Now that makes for an interesting expression.

It's the Quadratic Formula ^_^

Only one I dont get...

I have actually seen equations like this in a Physics class! except we prefer lower case xi, and tend to use subscripts. I was also using xi for three different things in my undergraduate research thesis. Seriously what is the fixation on xi

This is the kind of thing that if my teacher ever did I would either kill her or fall in love.

There's really a very fine line.

A mathematician friend of mine did a terribly complicated computation with too many steps. He will remain anonymous to protect the innocent.
Instead of breaking up the computation, he kept using new single letters for the variables. When he ran out the alphabet (twice, both upper and lowercase, including o and O!) he used greek letters, including small pi and capital sigma.
That was a bit hard to read, I promise.

Finding the best way to do a calculation is not always easy. I remember back in High School, my teacher was taking a graduate level aquatics chem course. He got a derivation from his prof in six steps that had been worked down over the course of several years from its original twelve steps. Between us, we got it down to three pretty easy steps.

Wow. I must have been out of the math world for too long. I never remember a fixation on the letter Xi. I do remember Saxon with his high school level math text books liking a lot of subscripts and making variables relate to the problem instead of always assuming the unknown quantity is the letter x.

This is perhaps the most horrible web comic i have ever read...