YES

---- CR(R)
---- [Knuth and Bendix, 1970]
R:
f(i(x),g(a())) -> f(j(x,x),g(b()))
b() -> a()
i(x) -> j(x,x)
CP(R):
f(j(___y8,___y8),g(a())) -> f(j(___y8,___y8),g(b()))