# Which are the conventions of typesetting a vector variable denoted by a Greek letter? [closed]

I have noticed that there are several ways to denote that a variable represent a vector, an arrow above, a tilde underneath, and typesetting the variable in bold non-italic font. I started using the latter, but ran into issues with Greek letters. I finally found a solution in the upgreek package, but the fact that this was not available in the default font makes me wonder if I am using a non-standard way to typeset vector variables.

Is there a preferred way of typesetting vector variables when they are denoted by Greek characters? Should they be upright and bold? Or upright, italicized and bold?

## closed as primarily opinion-based by Willie Wong, user36296, Werner, egreg, MenschAug 17 '16 at 17:45

Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise. If this question can be reworded to fit the rules in the help center, please edit the question.

• At the very least, specify your context. Mathematicians for example care not a jot whether your variable is a scalar or a vector, and would not ever imagine adorning the symbol or changing the font just because it is a vector. Physicists and engineers likely disagree. – Willie Wong Aug 17 '16 at 16:18
• @WillieWong Thanks for the comment, I just started a machine learning course online and I am taking notes using markdown and latex. The prof in that class uses the same variable for vectors as for anything else, but he enforces the notation verbally ("..let beta be a vector of..."). As I read a bit online, I saw that there were several recommendations for vector variable notation, so I am curious if there is one style that is generally preferred (maybe an ISO recommendation or something similar). – joelostblom Aug 17 '16 at 16:24
• There is an ISO recommendation; I refuse on principle to pay 150+ CHF to have someone dictate to me how to write my mathematics. – Willie Wong Aug 17 '16 at 16:26
• Note that, if you're not stuck to the default Computer Modern, there are quite a few fonts that offer the choice between upright or slanted for Greek Letters: fourier, kpfonts, Minion Pro, newpx or newtx. – Bernard Aug 17 '16 at 16:37
• @WillieWong -- besides being pricey, the iso recommendation was created by engineers and physicists, not by mathematicians, and some of the specified notation is not the accepted "mathematical way". (cf. disagreement regarding the differential d.) – barbara beeton Aug 17 '16 at 17:02