NO
0.08/0.18	NO
0.08/0.18	
0.08/0.18	Problem:
0.08/0.18	 U31(tt()) -> N
0.08/0.18	 U42(tt()) -> s(plus(N,M))
0.08/0.18	 U11(tt()) -> U12(isNat())
0.08/0.18	 U12(tt()) -> tt()
0.08/0.18	 U21(tt()) -> tt()
0.08/0.18	 U41(tt()) -> U42(isNat())
0.08/0.18	 isNat() -> tt()
0.08/0.18	 isNat() -> U11(isNat())
0.08/0.18	 isNat() -> U21(isNat())
0.08/0.18	 plus(N,0()) -> U31(isNat())
0.08/0.18	 plus(N,s(M)) -> U41(isNat())
0.08/0.18	
0.08/0.18	Proof:
0.08/0.18	 Fresh Variable Processor: loop length: 1
0.08/0.18	                           terms:
0.08/0.18	                            U31(tt())
0.08/0.18	                           context: []
0.08/0.18	                           substitution:
0.08/0.18	                            N -> U31(tt())
0.08/0.18	  Qed
0.08/0.18	EOF