MAYBE
Input TRS:
      1: a(x1) -> x1
      2: a(b(a(x1))) -> a(x1)
      3: b(a(a(b(x1)))) -> a(a(a(a(b(b(b(x1)))))))
      4: a(a(a(a(x1)))) -> b(x1)
Number of strict rules: 4
Direct POLO(bPol) ... failed.
Uncurrying ... failed.
Dependency Pairs:
     #1: #b(a(a(b(x1)))) -> #a(a(a(a(b(b(b(x1)))))))
     #2: #b(a(a(b(x1)))) -> #a(a(a(b(b(b(x1))))))
     #3: #b(a(a(b(x1)))) -> #a(a(b(b(b(x1)))))
     #4: #b(a(a(b(x1)))) -> #a(b(b(b(x1))))
     #5: #b(a(a(b(x1)))) -> #b(b(b(x1)))
     #6: #b(a(a(b(x1)))) -> #b(b(x1))
     #7: #a(a(a(a(x1)))) -> #b(x1)
Number of SCCs: 1, DPs: 7
  SCC { #1..7 }
POLO(Sum)... POLO(max)... QLPOS... POLO(mSum)... QWPOpS(mSum)... Mat2b... failed.
Finding a loop...  failed.