let R be the TRS under consideration

a(a(b(b(_1)))) -> a(a(a(a(a(_1))))) is in elim_R(R)
let r0 be the right-hand side of this rule
p0 = 0.0.0 is a position in r0
we have r0|p0 = a(a(_1))
a(a(b(b(_2)))) -> b(b(b(b(b(a(a(a(a(a(_2)))))))))) is in R
let l'0 be the left-hand side of this rule
theta0 = {_1/b(b(_2))} is a mgu of r0|p0 and l'0

==> a(a(b(b(b(b(_1)))))) -> a(a(a(b(b(b(b(b(a(a(a(a(a(_1))))))))))))) is in EU_R^1
let l be the left-hand side and r be the right-hand side of this rule
let p = 0
let theta = {}
let theta' = {_1/b(a(a(a(a(a(_1))))))}
we have r|p = a(a(b(b(b(b(b(a(a(a(a(a(_1)))))))))))) and
theta'(theta(l)) = theta(r|p)
so, theta(l) = a(a(b(b(b(b(_1)))))) is non-terminating w.r.t. R

Termination disproved by the forward process
proof stopped at iteration i=1, depth k=10
2 rule(s) generated