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The given Problem was:
a a a -> b a b 
b a b -> a b a 
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A self-embedding rewrite structure for the given SRS is:
   a a a b a a --(6)-> a a a b a a (#89)
   OC+OC at 1
      OC: a a a --(2)-> a b a (#5)
          OC+OC at 0
             OC: a a a --(1)-> b a b (#1)
                 Rule
             OC: b a b --(1)-> a b a (#2)
                 Rule
      OC: b a b a a --(4)-> a a b a a (#47)
          OC+OC at 1
             OC: b a b a a --(3)-> a b a b a (#7)
                 OC+OC at 2
                    OC: b a b --(1)-> a b a (#2)
                        Rule
                    OC: a a a --(2)-> a b a (#5)
                        OC+OC at 0
                           OC: a a a --(1)-> b a b (#1)
                               Rule
                           OC: b a b --(1)-> a b a (#2)
                               Rule
             OC: b a b --(1)-> a b a (#2)
                 Rule
Hence, the SRS is non-terminating.