is_emptyniltrueis_emptyconsxlfalsehdconsxlxtlconsxllappendl1l2ifappendl1l2l1ifappendl1l2nill2ifappendl1l2consxlconsxappendll22.1appendl1l2ifappendl1l2l1ifappendl1l2consxlappendll2true1append2111ifappend3113cons2112appendl1l2ifappendl1l2l1appendl1l2ifappendl1l2l1false
AProVE
d08497719f481e0c456d436c39d857ef33ce6dc3 rene 20120104 unpublished dirty
http://aprove.informatik.rwth-aachen.de/
John
Doe