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 = 5] f(u(d,h(d),_0),k(b),u(d,h(d),_0)) -> f(u(d,h(d),_0),k(b),u(d,h(d),_0)) Let l be the left-hand side and r be the right-hand side of this rule. Let p = epsilon, theta1 = {} and theta2 = {}. We have r|p = f(u(d,h(d),_0),k(b),u(d,h(d),_0)) and theta2(theta1(l)) = theta1(r|p). Hence, the term theta1(l) = f(u(d,h(d),_0),k(b),u(d,h(d),_0)) 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, 1 unfolded rule generated. # Iteration 1: no loop detected, 2 unfolded rules generated. # Iteration 2: no loop detected, 3 unfolded rules generated. # Iteration 3: no loop detected, 3 unfolded rules generated. # Iteration 4: no loop detected, 9 unfolded rules generated. # Iteration 5: loop detected, 7 unfolded rules generated. Here is the successful unfolding. Let IR be the TRS under analysis. L0 = f^#(k(a),k(b),_0) -> f^#(_0,_0,_0) is in U_IR^0. Let p0 = [0]. We unfold the rule of L0 backwards at position p0 with the rule u(d,c(_0),_1) -> k(_0). ==> L1 = f^#(u(d,c(a),_0),k(b),_1) -> f^#(_1,_1,_1) is in U_IR^1. Let p1 = [0, 1]. We unfold the rule of L1 backwards at position p1 with the rule h(d) -> c(a). ==> L2 = f^#(u(d,h(d),_0),k(b),_1) -> f^#(_1,_1,_1) is in U_IR^2. Let p2 = [0]. The subterm at position p2 in the left-hand side of the rule of L2 unifies with the subterm at position p2 in the right-hand side of the rule of L2. ==> L3 = f^#(u(d,h(d),_0),k(b),u(d,h(d),_0)) -> f^#(u(d,h(d),_0),u(d,h(d),_0),u(d,h(d),_0)) is in U_IR^3. Let p3 = [1, 1]. We unfold the rule of L3 forwards at position p3 with the rule h(d) -> c(b). ==> L4 = f^#(u(d,h(d),_0),k(b),u(d,h(d),_0)) -> f^#(u(d,h(d),_0),u(d,c(b),_0),u(d,h(d),_0)) is in U_IR^4. Let p4 = [1]. We unfold the rule of L4 forwards at position p4 with the rule u(d,c(_0),_1) -> k(_0). ==> L5 = f^#(u(d,h(d),_0),k(b),u(d,h(d),_0)) -> f^#(u(d,h(d),_0),k(b),u(d,h(d),_0)) is in U_IR^5. ** END proof description ** Proof stopped at iteration 5 Number of unfolded rules generated by this proof = 25 Number of unfolded rules generated by all the parallel proofs = 25