let R be the TRS under consideration

g(f(_1,_2)) -> g(g(_1)) is in elim_R(R)
let r0 be the right-hand side of this rule
p0 = 0 is a position in r0
we have r0|p0 = g(_1)
g(f(_3,_4)) -> f(f(g(g(_3)),g(g(_4))),f(g(g(_3)),g(g(_4)))) is in R
let l'0 be the left-hand side of this rule
theta0 = {_1/f(_3,_4)} is a mgu of r0|p0 and l'0

==> g(f(f(_1,_2),_3)) -> g(f(f(g(g(_1)),g(g(_2))),f(g(g(_1)),g(g(_2))))) is in EU_R^1
let l be the left-hand side and r be the right-hand side of this rule
let p = epsilon
let theta = {}
let theta' = {_1/g(g(_1)), _2/g(g(_2)), _3/f(g(g(_1)),g(g(_2)))}
we have r|p = g(f(f(g(g(_1)),g(g(_2))),f(g(g(_1)),g(g(_2))))) and
theta'(theta(l)) = theta(r|p)
so, theta(l) = g(f(f(_1,_2),_3)) is non-terminating w.r.t. R

Termination disproved by the forward process
proof stopped at iteration i=1, depth k=4
3 rule(s) generated