YES

Prover = TRS(tech=PATTERN_RULES, nb_unfoldings=unlimited, max_nb_unfolded_rules=200)

** BEGIN proof argument **
All the DP problems were proved finite.
As all the involved DP processors are sound,
the TRS under analysis terminates.
** 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 = [rev^#(++(_0,_1)) -> rev^#(_1), rev^#(++(_0,_1)) -> rev^#(_0)]
  TRS = {flatten(nil) -> nil, flatten(unit(_0)) -> flatten(_0), flatten(++(_0,_1)) -> ++(flatten(_0),flatten(_1)), flatten(++(unit(_0),_1)) -> ++(flatten(_0),flatten(_1)), flatten(flatten(_0)) -> flatten(_0), rev(nil) -> nil, rev(unit(_0)) -> unit(_0), rev(++(_0,_1)) -> ++(rev(_1),rev(_0)), rev(rev(_0)) -> _0, ++(_0,nil) -> _0, ++(nil,_0) -> _0, ++(++(_0,_1),_2) -> ++(_0,++(_1,_2))}
    ## Trying with homeomorphic embeddings... Success!
  This DP problem is finite.
  ## DP problem: 
  Dependency pairs = [flatten^#(unit(_0)) -> flatten^#(_0), flatten^#(++(_0,_1)) -> flatten^#(_0), flatten^#(++(_0,_1)) -> flatten^#(_1), flatten^#(++(unit(_0),_1)) -> flatten^#(_0), flatten^#(++(unit(_0),_1)) -> flatten^#(_1), flatten^#(flatten(_0)) -> flatten^#(_0)]
  TRS = {flatten(nil) -> nil, flatten(unit(_0)) -> flatten(_0), flatten(++(_0,_1)) -> ++(flatten(_0),flatten(_1)), flatten(++(unit(_0),_1)) -> ++(flatten(_0),flatten(_1)), flatten(flatten(_0)) -> flatten(_0), rev(nil) -> nil, rev(unit(_0)) -> unit(_0), rev(++(_0,_1)) -> ++(rev(_1),rev(_0)), rev(rev(_0)) -> _0, ++(_0,nil) -> _0, ++(nil,_0) -> _0, ++(++(_0,_1),_2) -> ++(_0,++(_1,_2))}
    ## Trying with homeomorphic embeddings... Success!
  This DP problem is finite.
  ## DP problem: 
  Dependency pairs = [++^#(++(_0,_1),_2) -> ++^#(_0,++(_1,_2)), ++^#(++(_0,_1),_2) -> ++^#(_1,_2)]
  TRS = {flatten(nil) -> nil, flatten(unit(_0)) -> flatten(_0), flatten(++(_0,_1)) -> ++(flatten(_0),flatten(_1)), flatten(++(unit(_0),_1)) -> ++(flatten(_0),flatten(_1)), flatten(flatten(_0)) -> flatten(_0), rev(nil) -> nil, rev(unit(_0)) -> unit(_0), rev(++(_0,_1)) -> ++(rev(_1),rev(_0)), rev(rev(_0)) -> _0, ++(_0,nil) -> _0, ++(nil,_0) -> _0, ++(++(_0,_1),_2) -> ++(_0,++(_1,_2))}
    ## Trying with homeomorphic embeddings... Failed!
    ## Trying with polynomial interpretations...
      The constraints are satisfied by the polynomials:
      {flatten(_0):[_0], unit(_0):[_0], ++(_0,_1):[_0 * _1], nil:[2], rev(_0):[_0], ++^#(_0,_1):[_0]}
      for all instantiations of the variables with values greater than or equal to mu = 2.
  This DP problem is finite.

** END proof description **

Proof stopped at iteration 0
Number of unfolded rules generated by this proof = 0
Number of unfolded rules generated by all the parallel proofs = 300