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] f(c,n__b,c) -> f(c,n__b,c)
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__b,c) and theta2(theta1(l)) = theta1(r|p).
Hence, the term theta1(l) = f(c,n__b,c) 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^#(n__a,n__b,_0) -> f^#(_0,_0,_0)]
  TRS = {f(n__a,n__b,_0) -> f(_0,_0,_0), c -> a, c -> b, a -> n__a, b -> n__b, activate(n__a) -> a, activate(n__b) -> b, activate(_0) -> _0}
    ## Trying with homeomorphic embeddings... Failed!
    ## Trying with polynomial interpretations... Too many coefficients (16)! Aborting!
    ## Trying with lexicographic path orders... Failed!
    ## Trying to prove nontermination by unfolding the dependency pairs with the rules of the TRS
      # max_depth=20, 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, 3 unfolded rules generated.
        # Iteration 3: nontermination not detected, 13 unfolded rules generated.
        # Iteration 4: nontermination not detected, 50 unfolded rules generated.
        # Iteration 5: nontermination detected, 12 unfolded rules generated.
        Here is the successful unfolding. Let IR be the TRS under analysis.
        L0 = f^#(n__a,n__b,_0) -> f^#(_0,_0,_0) [trans] is in U_IR^0.
        We build a unit triple from L0.
        ==> L1 = f^#(n__a,n__b,_0) -> f^#(_0,_0,_0) [unit] is in U_IR^1.
        Let p1 = [0].
        We unfold the rule of L1 backwards at position p1
        with the rule a -> n__a.
        ==> L2 = f^#(a,n__b,_0) -> f^#(_0,_0,_0) [unit] is in U_IR^2.
        Let p2 = [0].
        We unfold the rule of L2 backwards at position p2
        with the rule c -> a.
        ==> L3 = f^#(c,n__b,c) -> f^#(c,c,c) [unit] is in U_IR^3.
        Let p3 = [1].
        We unfold the rule of L3 forwards at position p3
        with the rule c -> b.
        ==> L4 = f^#(c,n__b,c) -> f^#(c,b,c) [unit] is in U_IR^4.
        Let p4 = [1].
        We unfold the rule of L4 forwards at position p4
        with the rule b -> n__b.
        ==> L5 = f^#(c,n__b,c) -> f^#(c,n__b,c) [unit] 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 = 80
Number of unfolded rules generated by all the parallel proofs = 153