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?