# How do I represent text with a mathematical expression?

How do I represent a text with a mathematical expression where the text is not a constant, function nor a variable? For example:

I have input in the format of $\text{fv}$[some integer] and $\text{pv}$[some integer] for each member of a set. I now want to classify each member of that set according to the integer values "attached" to $\text{fv}$ and $\text{pv}$.

An example is $\text{fv}8\text{fv}3$. However, the numbers are variable and so should probably be represented as $\text{fv}(x + y)\text{pv}(z)$ or perhaps $'\text{fv}'(x + y)'\text{pv}'(z)$. $\text{fv}$ and $\text{pv}$ are not constants, variables nor functions; they merely denote the referent to which $x + y$ and $z$ apply. The expression is not meant as $\text{fv}$ multiplied by (x + y) etc. The only mathematical part is to derive the numbers. However, I do want the notation to be mathematically sound as it will be incorporated into a larger mathematical expression.

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 Maybe subscripts? $(x+y)_{fv}(z)_{pv}$ – axblount Aug 17 '12 at 13:34