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 = 5] activate(n__adx(cons(_0,n__zeros))) -> activate(n__adx(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 = activate(n__adx(cons(0,n__zeros))) and theta2(theta1(l)) = theta1(r|p). Hence, the term theta1(l) = activate(n__adx(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! ## Applying the DP framework... ## Round 1: ## DP problem: Dependency pairs = [incr^#(cons(_0,_1)) -> activate^#(_1), activate^#(n__incr(_0)) -> incr^#(activate(_0)), adx^#(cons(_0,_1)) -> incr^#(cons(_0,n__adx(activate(_1)))), activate^#(n__adx(_0)) -> adx^#(activate(_0)), activate^#(n__incr(_0)) -> activate^#(_0), activate^#(n__adx(_0)) -> activate^#(_0), adx^#(cons(_0,_1)) -> activate^#(_1)] TRS = {incr(nil) -> nil, incr(cons(_0,_1)) -> cons(s(_0),n__incr(activate(_1))), adx(nil) -> nil, adx(cons(_0,_1)) -> incr(cons(_0,n__adx(activate(_1)))), nats -> adx(zeros), zeros -> cons(0,n__zeros), head(cons(_0,_1)) -> _0, tail(cons(_0,_1)) -> activate(_1), incr(_0) -> n__incr(_0), adx(_0) -> n__adx(_0), zeros -> n__zeros, activate(n__incr(_0)) -> incr(activate(_0)), activate(n__adx(_0)) -> adx(activate(_0)), activate(n__zeros) -> zeros, activate(_0) -> _0} ## Trying with homeomorphic embeddings... Failed! ## Trying with polynomial interpretations... Too many coefficients (26)! Aborting! ## Trying with lexicographic path orders... Failed! ## Trying to prove nontermination by unfolding the dependency pairs with the rules of the TRS # max_depth=4, unfold_variables=false: # Iteration 0: nontermination not detected, 7 unfolded rules generated. # Iteration 1: nontermination not detected, 33 unfolded rules generated. # Iteration 2: nontermination not detected, 74 unfolded rules generated. # Iteration 3: nontermination not detected, 188 unfolded rules generated. # Iteration 4: nontermination not detected, 376 unfolded rules generated. # Iteration 5: nontermination detected, 569 unfolded rules generated. Here is the successful unfolding. Let IR be the TRS under analysis. L0 = activate^#(n__adx(_0)) -> adx^#(activate(_0)) [trans] is in U_IR^0. D = adx^#(cons(_0,_1)) -> incr^#(cons(_0,n__adx(activate(_1)))) is a dependency pair of IR. We build a composed triple from L0 and D. ==> L1 = [activate^#(n__adx(_0)) -> adx^#(activate(_0)), adx^#(cons(_1,_2)) -> incr^#(cons(_1,n__adx(activate(_2))))] [comp] is in U_IR^1. Let p1 = [0]. We unfold the first rule of L1 forwards at position p1 with the rule activate(_0) -> _0. ==> L2 = activate^#(n__adx(cons(_0,_1))) -> incr^#(cons(_0,n__adx(activate(_1)))) [trans] is in U_IR^2. D = incr^#(cons(_0,_1)) -> activate^#(_1) is a dependency pair of IR. We build a composed triple from L2 and D. ==> L3 = [activate^#(n__adx(cons(_0,_1))) -> incr^#(cons(_0,n__adx(activate(_1)))), incr^#(cons(_2,_3)) -> activate^#(_3)] [comp] is in U_IR^3. Let p3 = [0, 1, 0]. We unfold the first rule of L3 forwards at position p3 with the rule activate(n__zeros) -> zeros. ==> L4 = [activate^#(n__adx(cons(_0,n__zeros))) -> incr^#(cons(_0,n__adx(zeros))), incr^#(cons(_1,_2)) -> activate^#(_2)] [comp] is in U_IR^4. Let p4 = [0, 1, 0]. We unfold the first rule of L4 forwards at position p4 with the rule zeros -> cons(0,n__zeros). ==> L5 = activate^#(n__adx(cons(_0,n__zeros))) -> activate^#(n__adx(cons(0,n__zeros))) [trans] is in U_IR^5. This DP problem is infinite. ** END proof description ** Proof stopped at iteration 5 Number of unfolded rules generated by this proof = 1247 Number of unfolded rules generated by all the parallel proofs = 8931