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 = 4] activate(n__f(n__g(g(_0)),_1)) -> activate(n__f(n__g(g(_0)),activate(_1))) Let l be the left-hand side and r be the right-hand side of this rule. Let p = epsilon, theta1 = {} and theta2 = {_1->activate(_1)}. We have r|p = activate(n__f(n__g(g(_0)),activate(_1))) and theta2(theta1(l)) = theta1(r|p). Hence, the term theta1(l) = activate(n__f(n__g(g(_0)),_1)) 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^#(g(_0),_1) -> f^#(_0,n__f(n__g(_0),activate(_1))), activate^#(n__f(_0,_1)) -> f^#(activate(_0),_1), activate^#(n__f(_0,_1)) -> activate^#(_0), activate^#(n__g(_0)) -> activate^#(_0), f^#(g(_0),_1) -> activate^#(_1)] TRS = {f(g(_0),_1) -> f(_0,n__f(n__g(_0),activate(_1))), f(_0,_1) -> n__f(_0,_1), g(_0) -> n__g(_0), activate(n__f(_0,_1)) -> f(activate(_0),_1), activate(n__g(_0)) -> g(activate(_0)), activate(_0) -> _0} ## Trying with homeomorphic embeddings... Failed! ## Trying with polynomial interpretations... Too many coefficients (15)! Aborting! ## Trying with lexicographic path orders... Failed! ## Trying to prove nontermination by unfolding the dependency pairs with the rules of the TRS # max_depth=3, unfold_variables=false: # Iteration 0: nontermination not detected, 5 unfolded rules generated. # Iteration 1: nontermination not detected, 18 unfolded rules generated. # Iteration 2: nontermination not detected, 29 unfolded rules generated. # Iteration 3: nontermination not detected, 32 unfolded rules generated. # Iteration 4: nontermination detected, 10 unfolded rules generated. Here is the successful unfolding. Let IR be the TRS under analysis. L0 = activate^#(n__f(_0,_1)) -> f^#(activate(_0),_1) [trans] is in U_IR^0. D = f^#(g(_0),_1) -> f^#(_0,n__f(n__g(_0),activate(_1))) is a dependency pair of IR. We build a composed triple from L0 and D. ==> L1 = [activate^#(n__f(_0,_1)) -> f^#(activate(_0),_1), f^#(g(_2),_3) -> f^#(_2,n__f(n__g(_2),activate(_3)))] [comp] is in U_IR^1. Let p1 = [0]. We unfold the first rule of L1 forwards at position p1 with the rule activate(n__g(_0)) -> g(activate(_0)). ==> L2 = [activate^#(n__f(n__g(_0),_1)) -> f^#(g(activate(_0)),_1), f^#(g(_2),_3) -> f^#(_2,n__f(n__g(_2),activate(_3)))] [comp] is in U_IR^2. Let p2 = [0, 0]. We unfold the first rule of L2 forwards at position p2 with the rule activate(_0) -> _0. ==> L3 = activate^#(n__f(n__g(_0),_1)) -> f^#(_0,n__f(n__g(_0),activate(_1))) [trans] is in U_IR^3. D = f^#(g(_0),_1) -> activate^#(_1) is a dependency pair of IR. We build a composed triple from L3 and D. ==> L4 = activate^#(n__f(n__g(g(_0)),_1)) -> activate^#(n__f(n__g(g(_0)),activate(_1))) [trans] is in U_IR^4. This DP problem is infinite. ** END proof description ** Proof stopped at iteration 4 Number of unfolded rules generated by this proof = 94 Number of unfolded rules generated by all the parallel proofs = 573