NO
* Step 1: Looptree NO
    + Considered Problem:
        Rules:
          0. f1(A,B,C,D) -> f1(-1 + A,B,C,D)             [A >= 1] (?,1)
          1. f1(A,B,C,D) -> f1(A + B,B + C,C + D,-1 + D) [A >= 1] (?,1)
          2. f0(A,B,C,D) -> f1(A,B,C,D)                  True     (1,1)
        Signature:
          {(f0,4);(f1,4)}
        Flow Graph:
          [0->{0,1},1->{0,1},2->{0,1}]
        
    + Applied Processor:
        Looptree
    + Details:
        We construct a looptree:
          P: [0,1,2]
          |
          `- p:[0,1] c: []

NO