MAYBE
* Step 1: TrivialSCCs MAYBE
    + Considered Problem:
        Rules:
          0. f0(A,B,C,D)  -> f4(0,B,C,D)         True                       (1,1)
          1. f4(A,B,C,D)  -> f8(1 + A,B,0,D)     [B >= 1 + A]               (?,1)
          2. f8(A,B,C,D)  -> f16(A,B,C,0)        [B >= 1 + A]               (?,1)
          3. f8(A,B,C,D)  -> f16(A,B,C,D)        [A >= B]                   (?,1)
          4. f8(A,B,C,D)  -> f8(1 + A,B,1 + C,E) [B >= 1 + A && 0 >= 1 + E] (?,1)
          5. f8(A,B,C,D)  -> f8(1 + A,B,1 + C,E) [B >= 1 + A && E >= 1]     (?,1)
          6. f16(A,B,C,D) -> f4(A,B,C,D)         [0 >= C]                   (?,1)
          7. f16(A,B,C,D) -> f4(-1 + A,B,C,D)    [C >= 1]                   (?,1)
          8. f4(A,B,C,D)  -> f20(A,B,C,D)        [A >= B]                   (?,1)
        Signature:
          {(f0,4);(f16,4);(f20,4);(f4,4);(f8,4)}
        Flow Graph:
          [0->{1,8},1->{2,3,4,5},2->{6,7},3->{6,7},4->{2,3,4,5},5->{2,3,4,5},6->{1,8},7->{1,8},8->{}]
        
    + Applied Processor:
        TrivialSCCs
    + Details:
        All trivial SCCs of the transition graph admit timebound 1.
* Step 2: AddSinks MAYBE
    + Considered Problem:
        Rules:
          0. f0(A,B,C,D)  -> f4(0,B,C,D)         True                       (1,1)
          1. f4(A,B,C,D)  -> f8(1 + A,B,0,D)     [B >= 1 + A]               (?,1)
          2. f8(A,B,C,D)  -> f16(A,B,C,0)        [B >= 1 + A]               (?,1)
          3. f8(A,B,C,D)  -> f16(A,B,C,D)        [A >= B]                   (?,1)
          4. f8(A,B,C,D)  -> f8(1 + A,B,1 + C,E) [B >= 1 + A && 0 >= 1 + E] (?,1)
          5. f8(A,B,C,D)  -> f8(1 + A,B,1 + C,E) [B >= 1 + A && E >= 1]     (?,1)
          6. f16(A,B,C,D) -> f4(A,B,C,D)         [0 >= C]                   (?,1)
          7. f16(A,B,C,D) -> f4(-1 + A,B,C,D)    [C >= 1]                   (?,1)
          8. f4(A,B,C,D)  -> f20(A,B,C,D)        [A >= B]                   (1,1)
        Signature:
          {(f0,4);(f16,4);(f20,4);(f4,4);(f8,4)}
        Flow Graph:
          [0->{1,8},1->{2,3,4,5},2->{6,7},3->{6,7},4->{2,3,4,5},5->{2,3,4,5},6->{1,8},7->{1,8},8->{}]
        
    + Applied Processor:
        AddSinks
    + Details:
        ()
* Step 3: Failure MAYBE
  + Considered Problem:
      Rules:
        0. f0(A,B,C,D)  -> f4(0,B,C,D)         True                       (1,1)
        1. f4(A,B,C,D)  -> f8(1 + A,B,0,D)     [B >= 1 + A]               (?,1)
        2. f8(A,B,C,D)  -> f16(A,B,C,0)        [B >= 1 + A]               (?,1)
        3. f8(A,B,C,D)  -> f16(A,B,C,D)        [A >= B]                   (?,1)
        4. f8(A,B,C,D)  -> f8(1 + A,B,1 + C,E) [B >= 1 + A && 0 >= 1 + E] (?,1)
        5. f8(A,B,C,D)  -> f8(1 + A,B,1 + C,E) [B >= 1 + A && E >= 1]     (?,1)
        6. f16(A,B,C,D) -> f4(A,B,C,D)         [0 >= C]                   (?,1)
        7. f16(A,B,C,D) -> f4(-1 + A,B,C,D)    [C >= 1]                   (?,1)
        8. f4(A,B,C,D)  -> f20(A,B,C,D)        [A >= B]                   (?,1)
        9. f4(A,B,C,D)  -> exitus616(A,B,C,D)  True                       (?,1)
      Signature:
        {(exitus616,4);(f0,4);(f16,4);(f20,4);(f4,4);(f8,4)}
      Flow Graph:
        [0->{1,8,9},1->{2,3,4,5},2->{6,7},3->{6,7},4->{2,3,4,5},5->{2,3,4,5},6->{1,8,9},7->{1,8,9},8->{},9->{}]
      
  + Applied Processor:
      LooptreeTransformer
  + Details:
      We construct a looptree:
        P: [0,1,2,3,4,5,6,7,8,9]
        |
        `- p:[1,6,2,4,5,3,7] c: [4,5]
           |
           `- p:[1,6,2,3,7] c: []
MAYBE