#### QUESTION

For example, I hate that Mathematica uses `Pochhammer`

symbol in outputs and prefer all the expressions in `Gamma`

function. How can I ban usage of `Pochhammer`

? I also want all outputs to use `HurwitzZeta`

rather than `Zeta`

.

In another instance I want the results to use my own variant of Polygamma function (modified). How can I mandate its usage when possible?

#### ANSWER

You may try for example something like:

```
f[e_] := 100 Count[e, _Pochhammer, {0, Infinity}] + LeafCount[e];
FullSimplify[Pochhammer[k, n], ComplexityFunction -> f]
(*
->Gamma[k + n]/Gamma[k]
*)
```

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