NO Prover = TRS(tech=GUIDED_UNF, nb_unfoldings=unlimited, unfold_variables=true, strategy=LEFTMOST_NE) ** BEGIN proof argument ** The following rule was generated while unfolding the analyzed TRS: [iteration = 3] isNatIList(n__cons(_0,n__zeros)) -> isNatIList(n__cons(0,n__zeros)) Let l be the left-hand side and r be the right-hand side of this rule. Let p = epsilon, theta1 = {} and theta2 = {_0->0}. We have r|p = isNatIList(n__cons(0,n__zeros)) and theta2(theta1(l)) = theta1(r|p). Hence, the term theta1(l) = isNatIList(n__cons(_0,n__zeros)) loops w.r.t. the analyzed TRS. ** END proof argument ** ** BEGIN proof description ** ## Searching for a generalized rewrite rule (a rule whose right-hand side contains a variable that does not occur in the left-hand side)... No generalized rewrite rule found! ## Searching for a loop by unfolding (unfolding of variable subterms: ON)... # Iteration 0: no loop detected, 39 unfolded rules generated. # Iteration 1: no loop detected, 167 unfolded rules generated. # Iteration 2: no loop detected, 1029 unfolded rules generated. # Iteration 3: loop detected, 168 unfolded rules generated. Here is the successful unfolding. Let IR be the TRS under analysis. L0 = isNatIList^#(n__cons(_0,_1)) -> isNatIList^#(activate(_1)) is in U_IR^0. Let p0 = [0]. We unfold the rule of L0 forwards at position p0 with the rule activate(n__zeros) -> zeros. ==> L1 = isNatIList^#(n__cons(_0,n__zeros)) -> isNatIList^#(zeros) is in U_IR^1. Let p1 = [0]. We unfold the rule of L1 forwards at position p1 with the rule zeros -> cons(0,n__zeros). ==> L2 = isNatIList^#(n__cons(_0,n__zeros)) -> isNatIList^#(cons(0,n__zeros)) is in U_IR^2. Let p2 = [0]. We unfold the rule of L2 forwards at position p2 with the rule cons(_0,_1) -> n__cons(_0,_1). ==> L3 = isNatIList^#(n__cons(_0,n__zeros)) -> isNatIList^#(n__cons(0,n__zeros)) is in U_IR^3. ** END proof description ** Proof stopped at iteration 3 Number of unfolded rules generated by this proof = 1403 Number of unfolded rules generated by all the parallel proofs = 2204