MAYBE
* Step 1: TrivialSCCs MAYBE
    + 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:
        TrivialSCCs
    + Details:
        All trivial SCCs of the transition graph admit timebound 1.
* Step 2: UnsatPaths MAYBE
    + 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]            (1,1)
          8. f4(A,B,C,D) -> f14(A,B,C,B)    [B = D]            (1,1)
        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 3: AddSinks MAYBE
    + 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]            (1,1)
          8. f4(A,B,C,D) -> f14(A,B,C,B)    [B = D]            (1,1)
        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:
        AddSinks
    + Details:
        ()
* Step 4: UnsatPaths MAYBE
    + 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)
          9.  f4(A,B,C,D) -> exitus616(A,B,C,D) True               (?,1)
          10. f6(A,B,C,D) -> exitus616(A,B,C,D) True               (?,1)
        Signature:
          {(exitus616,4);(f0,4);(f14,4);(f4,4);(f6,4);(f7,4)}
        Flow Graph:
          [0->{5,6},1->{5,6},2->{3,4,8,9},3->{0,1,7,10},4->{0,1,7,10},5->{3,4,8,9},6->{3,4,8,9},7->{},8->{},9->{}
          ,10->{}]
        
    + Applied Processor:
        UnsatPaths
    + Details:
        We remove following edges from the transition graph: [(2,3),(2,8)]
* Step 5: Failure MAYBE
  + 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)
        9.  f4(A,B,C,D) -> exitus616(A,B,C,D) True               (?,1)
        10. f6(A,B,C,D) -> exitus616(A,B,C,D) True               (?,1)
      Signature:
        {(exitus616,4);(f0,4);(f14,4);(f4,4);(f6,4);(f7,4)}
      Flow Graph:
        [0->{5,6},1->{5,6},2->{4,9},3->{0,1,7,10},4->{0,1,7,10},5->{3,4,8,9},6->{3,4,8,9},7->{},8->{},9->{}
        ,10->{}]
      
  + Applied Processor:
      LooptreeTransformer
  + Details:
      We construct a looptree:
        P: [0,1,2,3,4,5,6,7,8,9,10]
        |
        `- p:[0,3,5,1,4,6] c: []
MAYBE