NO

Prover = TRS(tech=GUIDED_UNF, nb_unfoldings=unlimited, unfold_variables=true, strategy=LEFTMOST_NE)

** BEGIN proof argument **
The following rule was generated while unfolding the analyzed TRS:
[iteration = 6] active(f(active(c),b,active(c))) -> active(f(active(c),b,active(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 = active(f(active(c),b,active(c))) and theta2(theta1(l)) = theta1(r|p).
Hence, the term theta1(l) = active(f(active(c),b,active(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!

## Searching for a loop by unfolding (unfolding of variable subterms: ON)...
# Iteration 0: no loop detected, 2 unfolded rules generated.
# Iteration 1: no loop detected, 2 unfolded rules generated.
# Iteration 2: no loop detected, 25 unfolded rules generated.
# Iteration 3: no loop detected, 317 unfolded rules generated.
# Iteration 4: no loop detected, 4094 unfolded rules generated.
# Iteration 5: no loop detected, 54050 unfolded rules generated.
# Iteration 6: loop detected, 64213 unfolded rules generated.
Here is the successful unfolding. Let IR be the TRS under analysis.
L0 = [active^#(f(a,b,_0)) -> mark^#(f(_0,_0,_0)), mark^#(f(_1,_2,_3)) -> active^#(f(_1,_2,mark(_3)))] is in U_IR^0.
We merge the first and the second rule of L0.
==> L1 = active^#(f(a,b,_0)) -> active^#(f(_0,_0,mark(_0))) is in U_IR^1.
Let p1 = [0].
We unfold the rule of L1 forwards at position p1
with the rule f(_0,_1,mark(_2)) -> f(_0,_1,_2).
==> L2 = active^#(f(a,b,_0)) -> active^#(f(_0,_0,_0)) is in U_IR^2.
Let p2 = [0].
We unfold the rule of L2 backwards at position p2
with the rule f(mark(_0),_1,_2) -> f(_0,_1,_2).
==> L3 = active^#(f(mark(a),b,_0)) -> active^#(f(_0,_0,_0)) is in U_IR^3.
Let p3 = [0, 0].
We unfold the rule of L3 backwards at position p3
with the rule active(c) -> mark(a).
==> L4 = active^#(f(active(c),b,active(c))) -> active^#(f(active(c),active(c),active(c))) is in U_IR^4.
Let p4 = [0, 1].
We unfold the rule of L4 forwards at position p4
with the rule active(c) -> mark(b).
==> L5 = active^#(f(active(c),b,active(c))) -> active^#(f(active(c),mark(b),active(c))) is in U_IR^5.
Let p5 = [0].
We unfold the rule of L5 forwards at position p5
with the rule f(_0,mark(_1),_2) -> f(_0,_1,_2).
==> L6 = active^#(f(active(c),b,active(c))) -> active^#(f(active(c),b,active(c))) is in U_IR^6.

** END proof description **

Proof stopped at iteration 6
Number of unfolded rules generated by this proof = 122703
Number of unfolded rules generated by all the parallel proofs = 321896