Use italics for any letters used as symbols (eg constants, variables) to distinguish them from ordinary text:
Preferably, use 1-letter symbols (with or without subscripts and superscripts) for variables to avoid confusion with a product of 2 symbols (which are shown closed up when there is no multiplication operator):
Use plain text rather than italics for mathematical functions and variables where abbreviations of whole words are used:
log exp sin avg min
APG = net increase (births – deaths) + NOM
where APG = annual population growth, NOM = net overseas migration
Set vectors either in bold (roman) or in italics with an arrow above. Matrices and tensors are set in bold; however, note that there are more specific standards in particular fields regarding roman or italic type, and upper or lower case, so consult an expert:
Vector: f or \(\vec{f}\)
Tensor: S
Italicise Greek symbols:
