[bo1024]

It's more some level of what they call "mathematical maturity", or just experience with math. None of this relies on math past the first or second year of college for a typical STEM degree: linear algebra and vector calculus. But most people aren't used to the notation that is taken for granted here, for example, subscripts on functions.

I know it looks scary if you aren't used to it, but it just takes some practice to pick up. This is far from arcane and elite in the math world!

[bjornsing]

I still remember the formal prerequisite for one of the more advanced math courses I took at uni: “The mathematical maturity that several years of study in mathematics typically gives” (roughly translated from Swedish). I thought it was kind if pretentious at the time (most other courses listed other courses as prerequisites), but now I think it makes sense.