19.1 Description of Setoid_replace

## 19.1 Description of `Setoid_replace`

Working on user-defined structures in Coq is not very easy if Leibniz equality does not denote the intended equality. For example using lists to denote finite sets drive to difficulties since two non convertible terms can denote the same set.
We present here a Coq module, `Setoid_replace`, which allow to structure and automate some parts of the work. In particular, if everything has been registered a simple tactic can do replacement just as if the two terms were equal.