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] adx(cons(_0,n__zeros)) -> 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 = adx(cons(0,n__zeros)) and theta2(theta1(l)) = theta1(r|p). Hence, the term theta1(l) = 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^#(_0), adx^#(cons(_0,_1)) -> incr^#(cons(_0,n__adx(activate(_1)))), activate^#(n__adx(_0)) -> adx^#(_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(_0), activate(n__adx(_0)) -> adx(_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, 5 unfolded rules generated. # Iteration 1: nontermination not detected, 16 unfolded rules generated. # Iteration 2: nontermination not detected, 26 unfolded rules generated. # Iteration 3: nontermination not detected, 57 unfolded rules generated. # Iteration 4: nontermination detected, 37 unfolded rules generated. Here is the successful unfolding. Let IR be the TRS under analysis. L0 = adx^#(cons(_0,_1)) -> incr^#(cons(_0,n__adx(activate(_1)))) [trans] is in U_IR^0. D = incr^#(cons(_0,_1)) -> activate^#(_1) is a dependency pair of IR. We build a composed triple from L0 and D. ==> L1 = [adx^#(cons(_0,_1)) -> incr^#(cons(_0,n__adx(activate(_1)))), incr^#(cons(_2,_3)) -> activate^#(_3)] [comp] is in U_IR^1. Let p1 = [0, 1, 0]. We unfold the first rule of L1 forwards at position p1 with the rule activate(n__zeros) -> zeros. ==> L2 = [adx^#(cons(_0,n__zeros)) -> incr^#(cons(_0,n__adx(zeros))), incr^#(cons(_1,_2)) -> activate^#(_2)] [comp] is in U_IR^2. Let p2 = [0, 1, 0]. We unfold the first rule of L2 forwards at position p2 with the rule zeros -> cons(0,n__zeros). ==> L3 = adx^#(cons(_0,n__zeros)) -> activate^#(n__adx(cons(0,n__zeros))) [trans] is in U_IR^3. D = activate^#(n__adx(_0)) -> adx^#(_0) is a dependency pair of IR. We build a composed triple from L3 and D. ==> L4 = adx^#(cons(_0,n__zeros)) -> adx^#(cons(0,n__zeros)) [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 = 141 Number of unfolded rules generated by all the parallel proofs = 1122