I am currently writing up a research project, and I came across the following problem: I am running out of variable names. Most Latin and Greek letters are already in use.
In the write-up, we used many auxiliary variables (as calculations otherwise become very lengthy). Currently, the same symbol is in use multiple times (e.g., A, B, C). I assume that this is something that should be avoided so that every symbol only has one meaning that does not change in the course of the paper. Furthermore, I am wondering whether there is a convention for naming these variables. Currently, I am thinking about upper case names (as lower case variables are used in the model). Using superscripts is one option, but again, I am not sure where to begin, $A_a$ looks not right as does $A_1$.
Is there a convention or guide on how to approach this subject?