I keep a collection of ambiguities and oddities in mathematical notation at whystartat.xyz/wiki/Main_Page.
Are there any unresolved ambiguities in the standard style of drawing geometrical diagrams?
(is there a standard style of drawing geometrical diagrams?)

@christianp Not related to geometric diagrams, but the standard notation for elliptic integrals is hellacious. A decent chunk of the text on en.wikipedia.org/wiki/Elliptic is dedicated to explaining all the different notations. F(phi, k), F(phi | k^2), F(x; k), F(phi \ alpha). This is especially bad in a computing context because (except for maybe Mathematica) programming languages don't let you use those other delimiters, so it all turns into F(a, b): good luck guessing which notation it corresponds to!

Semicolon as a delimiter shows up in the notation for the hypergeometric function 2F1(a, b; c; z), but at least there you know what the parameters of the function are. Semicolon and pipe also show up in probability, which you mention on the Probability Theory page.

@apocheir @christianp I wrote about the notational thicket for Legendre-Jacobi elliptic integrals a long time ago: math.stackexchange.com/a/10865 . As for hypergeometric functions, I personally prefer $${}_2 F_1\left({{a,b}\atop{c}}\middle| z\right)$$ to $${}_2 F_1\left(a,b;c;z\right)$$ because I don't have to count to where the semicolon is (among other reasons), which becomes even more important for the general case $${}_p F_q$$. The social network of the future: No ads, no corporate surveillance, ethical design, and decentralization! Own your data with Mastodon!