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Is there a guide or source of inspiration I can use when picking variable and constant names for a mathematical formula? I'm in the process of converting a poorly written technical document into something cleaner, and I'm faced with garbage like this:

$HWP\_cur_x=Cut\_cur\times\sum^{ru\left(\frac{yr\_cur-start\_date}{Freq\_cur_x}\right)}_{t=0}f(Decay\_cur_x;yr\_cur-start\_date_x)$

I have a background in scientific computing, so I can appreciate an elegantly constructed formula, but I've always wondered how a good mathematician would choose variable names.

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    See [this post](http://math.stackexchange.com/questions/24241/why-do-mathematicians-use-single-letter-variables).2011-11-27

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If you're going to introduce single-letter variable names, it's important that (a) you only do it when it really will make the expression clearer, and (b) you provide full explanations for what your variables are? For example:

Let

$\begin{align} \tau & = \textrm{year} - \textrm{start date} \\ f & = \rm frequency \\ r & = \textrm{...description of what ru is} \\ T & = {r\tau/f} \\ d & = \rm decay \end{align} $

then

$HWP={\rm cut} \times \sum^{T}_{t=0} f(d;\tau)$

Here I followed the common convention of using $t$-like variables ($t$, $T$, $\tau$) to represent times and $f$ to represent a frequency. For the other variables I used the first letter of their names.

Note that this equation doesn't really make sense - the dummy variable in the summation is $t$, but $t$ doesn't appear anywhere in the summand. That should be fixed.