NO Prover = TRS(tech=GUIDED_UNF_TRIPLES, nb_unfoldings=unlimited, unfold_variables=false, max_nb_coefficients=12, max_nb_unfolded_rules=-1, strategy=LEFTMOST_NE) ** BEGIN proof argument ** The following rule was generated while unfolding the analyzed TRS: [iteration = 7] f(c,n__g(c),n__g(b)) -> f(c,n__g(c),n__g(b)) 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(c,n__g(c),n__g(b)) and theta2(theta1(l)) = theta1(r|p). Hence, the term theta1(l) = f(c,n__g(c),n__g(b)) 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! ## Applying the DP framework... ## Round 1: ## DP problem: Dependency pairs = [f^#(_0,n__g(_0),_1) -> f^#(activate(_1),activate(_1),activate(_1))] TRS = {f(_0,n__g(_0),_1) -> f(activate(_1),activate(_1),activate(_1)), g(b) -> c, b -> c, g(_0) -> n__g(_0), activate(n__g(_0)) -> g(activate(_0)), activate(_0) -> _0} ## Trying with homeomorphic embeddings... Failed! ## Trying with polynomial interpretations... Too many coefficients (17)! Aborting! ## Trying with lexicographic path orders... Failed! ## Trying to prove nontermination by unfolding the dependency pairs with the rules of the TRS # max_depth=2, unfold_variables=false: # Iteration 0: nontermination not detected, 1 unfolded rule generated. # Iteration 1: nontermination not detected, 1 unfolded rule generated. # Iteration 2: nontermination not detected, 2 unfolded rules generated. # Iteration 3: nontermination not detected, 2 unfolded rules generated. # Iteration 4: nontermination not detected, 2 unfolded rules generated. # Iteration 5: nontermination not detected, 0 unfolded rule generated. Nontermination not detected! # max_depth=2, unfold_variables=true: # Iteration 0: nontermination not detected, 1 unfolded rule generated. # Iteration 1: nontermination not detected, 1 unfolded rule generated. # Iteration 2: nontermination not detected, 2 unfolded rules generated. # Iteration 3: nontermination not detected, 2 unfolded rules generated. # Iteration 4: nontermination not detected, 1 unfolded rule generated. # Iteration 5: nontermination not detected, 1 unfolded rule generated. # Iteration 6: nontermination not detected, 3 unfolded rules generated. # Iteration 7: nontermination not detected, 0 unfolded rule generated. Nontermination not detected! # max_depth=3, unfold_variables=false: # Iteration 0: nontermination not detected, 1 unfolded rule generated. # Iteration 1: nontermination not detected, 1 unfolded rule generated. # Iteration 2: nontermination not detected, 4 unfolded rules generated. # Iteration 3: nontermination not detected, 8 unfolded rules generated. # Iteration 4: nontermination not detected, 16 unfolded rules generated. # Iteration 5: nontermination not detected, 19 unfolded rules generated. # Iteration 6: nontermination not detected, 31 unfolded rules generated. # Iteration 7: nontermination detected, 23 unfolded rules generated. Here is the successful unfolding. Let IR be the TRS under analysis. L0 = f^#(_0,n__g(_0),_1) -> f^#(activate(_1),activate(_1),activate(_1)) [trans] is in U_IR^0. We build a unit triple from L0. ==> L1 = f^#(_0,n__g(_0),_1) -> f^#(activate(_1),activate(_1),activate(_1)) [unit] is in U_IR^1. Let p1 = [0]. We unfold the rule of L1 forwards at position p1 with the rule activate(n__g(_0)) -> g(activate(_0)). ==> L2 = f^#(_0,n__g(_0),n__g(_1)) -> f^#(g(activate(_1)),activate(n__g(_1)),activate(n__g(_1))) [unit] is in U_IR^2. Let p2 = [0, 0]. We unfold the rule of L2 forwards at position p2 with the rule activate(_0) -> _0. ==> L3 = f^#(_0,n__g(_0),n__g(_1)) -> f^#(g(_1),activate(n__g(_1)),activate(n__g(_1))) [unit] is in U_IR^3. Let p3 = [0]. We unfold the rule of L3 forwards at position p3 with the rule g(b) -> c. ==> L4 = f^#(c,n__g(c),n__g(b)) -> f^#(c,activate(n__g(b)),activate(n__g(b))) [unit] is in U_IR^4. Let p4 = [1]. We unfold the rule of L4 forwards at position p4 with the rule activate(_0) -> _0. ==> L5 = f^#(c,n__g(c),n__g(b)) -> f^#(c,n__g(b),activate(n__g(b))) [unit] is in U_IR^5. Let p5 = [1, 0]. We unfold the rule of L5 forwards at position p5 with the rule b -> c. ==> L6 = f^#(c,n__g(c),n__g(b)) -> f^#(c,n__g(c),activate(n__g(b))) [unit] is in U_IR^6. Let p6 = [2]. We unfold the rule of L6 forwards at position p6 with the rule activate(_0) -> _0. ==> L7 = f^#(c,n__g(c),n__g(b)) -> f^#(c,n__g(c),n__g(b)) [unit] is in U_IR^7. This DP problem is infinite. ** END proof description ** Proof stopped at iteration 7 Number of unfolded rules generated by this proof = 122 Number of unfolded rules generated by all the parallel proofs = 609