--filter=action_labels

[jacopol]

The option --filter is described in the manpage, but it is not clear that you can give it value "action_labels".

This option is currently necessary, since LTSmin adds the guards in a specification as state labels.
These state labels also occur in the generated state space by default, blocking ltsmin-reduce.
This mainly affects mcrl2 users that want to generate and minimize a state space.

Ideally, lps2lts-mc should not write the state labels that are generated internally by default.