MAYBE

Problem:
 t(f(x1)) -> t(c(n(x1)))
 n(f(x1)) -> f(n(x1))
 o(f(x1)) -> f(o(x1))
 n(s(x1)) -> f(s(x1))
 o(s(x1)) -> f(s(x1))
 c(f(x1)) -> f(c(x1))
 c(n(x1)) -> n(c(x1))
 c(o(x1)) -> o(c(x1))
 c(o(x1)) -> o(x1)

Proof:
 Open