NO
* Step 1: UnsatPaths NO
    + Considered Problem:
        Rules:
          0. f6(A,B,C,D) -> f7(A,B,C,D)     [0 >= 1 + A]       (?,1)
          1. f6(A,B,C,D) -> f7(A,B,C,D)     [A >= 1]           (?,1)
          2. f0(A,B,C,D) -> f4(A,B,C,1 + B) [B >= 0 && C >= B] (1,1)
          3. f4(A,B,C,D) -> f6(E,B,C,D)     [B >= 1 + D]       (?,1)
          4. f4(A,B,C,D) -> f6(E,B,C,D)     [D >= 1 + B]       (?,1)
          5. f7(A,B,C,D) -> f4(A,B,C,1 + D) [C >= D]           (?,1)
          6. f7(A,B,C,D) -> f4(A,B,C,0)     [D >= 1 + C]       (?,1)
          7. f6(A,B,C,D) -> f14(0,B,C,D)    [A = 0]            (?,1)
          8. f4(A,B,C,D) -> f14(A,B,C,B)    [B = D]            (?,1)
        Signature:
          {(f0,4);(f14,4);(f4,4);(f6,4);(f7,4)}
        Flow Graph:
          [0->{5,6},1->{5,6},2->{3,4,8},3->{0,1,7},4->{0,1,7},5->{3,4,8},6->{3,4,8},7->{},8->{}]
        
    + Applied Processor:
        UnsatPaths
    + Details:
        We remove following edges from the transition graph: [(2,3),(2,8)]
* Step 2: FromIts NO
    + Considered Problem:
        Rules:
          0. f6(A,B,C,D) -> f7(A,B,C,D)     [0 >= 1 + A]       (?,1)
          1. f6(A,B,C,D) -> f7(A,B,C,D)     [A >= 1]           (?,1)
          2. f0(A,B,C,D) -> f4(A,B,C,1 + B) [B >= 0 && C >= B] (1,1)
          3. f4(A,B,C,D) -> f6(E,B,C,D)     [B >= 1 + D]       (?,1)
          4. f4(A,B,C,D) -> f6(E,B,C,D)     [D >= 1 + B]       (?,1)
          5. f7(A,B,C,D) -> f4(A,B,C,1 + D) [C >= D]           (?,1)
          6. f7(A,B,C,D) -> f4(A,B,C,0)     [D >= 1 + C]       (?,1)
          7. f6(A,B,C,D) -> f14(0,B,C,D)    [A = 0]            (?,1)
          8. f4(A,B,C,D) -> f14(A,B,C,B)    [B = D]            (?,1)
        Signature:
          {(f0,4);(f14,4);(f4,4);(f6,4);(f7,4)}
        Flow Graph:
          [0->{5,6},1->{5,6},2->{4},3->{0,1,7},4->{0,1,7},5->{3,4,8},6->{3,4,8},7->{},8->{}]
        
    + Applied Processor:
        FromIts
    + Details:
        ()
* Step 3: CloseWith NO
    + Considered Problem:
        Rules:
          f6(A,B,C,D) -> f7(A,B,C,D)      [0 >= 1 + A]
          f6(A,B,C,D) -> f7(A,B,C,D)      [A >= 1]
          f0(A,B,C,D) -> f4(A,B,C,1 + B)  [B >= 0 && C >= B]
          f4(A,B,C,D) -> f6(E,B,C,D)      [B >= 1 + D]
          f4(A,B,C,D) -> f6(E,B,C,D)      [D >= 1 + B]
          f7(A,B,C,D) -> f4(A,B,C,1 + D)  [C >= D]
          f7(A,B,C,D) -> f4(A,B,C,0)      [D >= 1 + C]
          f6(A,B,C,D) -> f14(0,B,C,D)     [A = 0]
          f4(A,B,C,D) -> f14(A,B,C,B)     [B = D]
        Signature:
          {(f0,4);(f14,4);(f4,4);(f6,4);(f7,4)}
        Rule Graph:
          [0->{5,6},1->{5,6},2->{4},3->{0,1,7},4->{0,1,7},5->{3,4,8},6->{3,4,8},7->{},8->{}]
    + Applied Processor:
        CloseWith False
    + Details:
        ()

NO