YES
Input TRS:
    1: f(f(x)) -> f(g(f(x)))
    2: f(x) -> x
Infeasibility test:
    x --> g(x)
Co-Order(NegReal,≥,Sum) ...Co-QLPOpS ...Co-QWPOpS(PosReal,>,Sum) ... succeeded.
     f(x1)	weight: (/ 1 2) + x1	status: []	precedence above:
    #(x1)	weight: x1	status: x1
     g(x1)	weight: x1	status: [x1]	precedence above: