Termination w.r.t. Q of the given QTRS could be disproven:

(0) Obligation:

Q restricted rewrite system:
The TRS R consists of the following rules:

a(b(b(x1))) → b(b(a(a(x1))))
a(a(x1)) → b(x1)

Q is empty.

(1) NonTerminationProof (EQUIVALENT transformation)

We used the non-termination processor [OPPELT08] to show that the SRS problem is infinite.

Found the self-embedding DerivationStructure:

a b b b b b b → b b a b b b b b b

a b b b b b b → b b a b b b b b b
by OverlapClosure OC 2

a b b → b b a a
by original rule (OC 1)

a b b b b → b b b b b b
by OverlapClosure OC 3

a b b b b → b b a b b b
by OverlapClosure OC 2

a b b → b b a a
by original rule (OC 1)

a b b → b b b
by OverlapClosure OC 2

a b b → b b a a
by original rule (OC 1)

a a → b
by original rule (OC 1)

a b b → b b b
by OverlapClosure OC 2

a b b → b b a a
by original rule (OC 1)

a a → b
by original rule (OC 1)

(2) NO