# Dealing with many entities that need a symbol

What does one do when one needs a lot of symbols and one has exhausted the useful symbols of the latin and greek alphabets? (I say useful symbols because letters like iota (ι) and upsilon (υ) seem too close to “i” and “u” or nu (ν) to be useful.)

What is the next most common list of symbols used in mathematics? Or, does one resort to referring entities in equations using longer words?

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Aside of the comment to use the Hebrew alphabet, I should add a short story and a remark on notational nightmares:

One of my friends decided that he is annoyed with the usual $x$ and $t$ variables. He submitted a homework assignment in ODE where all the variables were replaced by full words or drawings of flowers and buttons. The objects were chosen to fit several Hebrew based jokes.

The homework were graded and returned a week or two later, his grade was good but whoever graded it left a message on the last page:

Also, whatever you choose to use make sure it is not something which has a very concrete meaning. Write $f\colon\mathbb R^3\to\mathbb R$ as: $$f(\aleph_1,\aleph_2,\aleph_3)=\aleph_1+\frac{\aleph_2}{\aleph_3}$$
Careful and appropriate use of subscripts and superscripts is often the best approach. If you truly need to distinguish between 40+ variables, parameters, etc., your readers are going to have a hard time following you without being distracted by unusual symbols. In the case that sub/superscripts won’t work, I would use double-character variables and put spaces in where necessary, e.g., $aa\,bb+ab/ij=cc$. The little space between $aa$ and $bb$ is from \,, maybe an explicit $aa\cdot bb$ is clearer.