U11ttNU21ttsplusNMU41ttplusxNMNandttXU31tt0isNatttisNatandisNatisNatisNatplusN0U11isNatplusNsMU21andisNatxN0U31isNatxNsMU41andisNat2.0
AProVE
cb833845625c1ead9ffe8258c791cc945104daa0 rene 20110429 unpublished dirty
http://aprove.informatik.rwth-aachen.de/
John
Doe