# Notes on the `copar` library

In the first versions of this tool, I used the `copar` library:
[CoPaR (The Coalgebraic Partition Refiner)](https://git8.cs.fau.de/software/copar).
This is a great library and in particular very fast. Despite that, I switched
to my own partition refinement implementations because of the reasons below.
The last commit to use `copar` is `2b8b79a4`.

* I needed witnesses for some tasks. So I not only construct a partition,
  but also a splitting tree, where are track all the actions needed to
  separate states.

* I prefer to use the actual strings (or other data type) for the states,
  inputs and outputs as opposed to `Int`s. This makes it easier to debug, and
  less error-prone, as one cannot mix these entities anymore.

* `copar` comes with many dependencies, and it was a bit tricky to get the
  versioning correct.