The temporal logic prover `ls4` is available at .
Thank you very much. I download it now. It is referenced by my toolbox but
since it was no longer available... And anyway it deserves to be used by itself.
(There is a library that is already compiled I just hope it is not compiled with the
most recent linux libraries because my box is about 5 years old. I sometimes try to
persuade people to use old libraries but with no success until now.)