Notation diversity This morning I had a brief discussion about different notations of trigonometric functions in Europe, so I looked for an online resource dealing with these diversities in mathematical notation. I found this paper treating the issue. It links to a website called Notation census which aims to deal with the diversity by listing the variations in the notation around the world. Still, I find it quite hard to browse the site and feel that lot of things are still not included in its database. Therefore, my question is: do you know of a book or a website compiling these differences in notation in which one can find the most of the non-orthodox symbols and abbreviations used in the world?
 A: Christine Müller has collected a variety of examples to illustrate the diversity of notation, in the Survey on Mathematical Notations. Diversity exists because of distinct reasons:

*

*level of expertise ($a\div b$ in elementary school, versus
$\frac{a}{b}$ in high school)

*individual styles ($A\subseteq B$ or $A\subseteqq B$)

*cultural habits (anglo-saxon $(0,1]$ versus french $]0,1]$, or german 0,5 versus english 0.5; my personal example is https://hsm.stackexchange.com/questions/5644/why-did-i-learn-to-write-the-base-of-the-logarithm-differently-from-the-rest-of )

*area of application ($i$ in mathematics is $j$ in engineering, $\neq$ in mathematics is $!\!\!=$ in computer science, $\bar{z}$ in mathematics is $z^\ast$ in physics, $A^\ast$ in mathematics is $A^\dagger$ in physics – to no end of confusion ...)

*mistakes (arcsinh instead of arsinh)

This all addresses notation that is diverse but still commonly used. For non-orthodox notation I could offer Richard Feynman's trigonometric notation:



While I was doing all this trigonometry [as a teenager], I didn't like
the symbols for sine, cosine, tangent, and so on. To me, "sin f"
looked like s times i times n times f! So I invented another symbol,
like a square root sign, that was a sigma with a long arm sticking out
of it, and I put the f underneath. For the tangent it was a tau with
the top of the tau extended, and for the cosine I made a kind of
gamma, but it looked a little bit like the square root sign.
Now the
inverse sine was the same sigma, but left-to-right reflected so that
it started with the horizontal line with the value underneath, and
then the sigma. That was the inverse sine, NOT $\sin^{-1} f$ – that
was crazy! They had that in books! To me, $\sin^{-1}$ meant 1/sine,
the reciprocal. So my symbols were better.
I didn't like f(x) – that looked to me like f times X. I also didn't
like dy/dx-you have a tendency to cancel the d's, so I made a different
sign, something like an & sign. For logarithms it was a big L extended
to the right, with the thing you take the log of inside, and so on.
I thought my symbols were just as good, if not better, than the regular
symbols – it doesn't make any difference what symbols you use but I
discovered later that it does make a difference. Once when I was
explaining something to another kid in high school, without thinking I
started to make these symbols, and he said, "What the hell are those?"
I realized then that if I'm going to talk to anybody else, I'll have
to use the standard symbols, so I eventually gave up my own symbols.

from: Surely You're Joking, Mr. Feynman!

