More generally, the IUPAC and IUPAP defined in depth typesettings notations for everything related to physics (IUPAP) or Chemistry (IUPAC). They also give general guidelines for general typesetting.

As a chemist, I personaly use a lot the green book about Quantities, Units, and Symbols in physical chemistry published by the IUPAC (which is freely available) .

Those two organizations define really thoroughly all kinds of notations (see pages 183 to 193 of the green book for examples) which is extremely convenient for typesetting in those domains.

For example, they recommend a roman j when it stands as an equivalent of i for complex numbers to be sure that it is not confused with a surfacic current j which should be in italic.

They also published some recommendations on how to represent chemical molecules in a one hundred and thirty pages long manual (Graphical Representation Standards for Chemical Structure Diagams). The effort of standarzing the field of chemistry and physics is greatly improved tanks to the IUPAC and IUPAP. As a student, I thought that these organizations were useless but as a teacher, it is a really valuable tool. Having standardized definitions and notations is the best way to have the right words and the right notations for everything.

It is quite strange that there are only some sparse recommendations (ISO rules) for purely mathematical typesetting. I am not aware of something similar for mathematics where a lot of efforts are devoted to standardize notations and definitions (on an international scale).

-- Martin Verot (email)