MAYBE
* Step 1: TrivialSCCs MAYBE
    + Considered Problem:
        Rules:
          0. f1(A,B,C,D) -> f300(A,B,C,E)   [A >= B && A >= 1 + B]          (?,1)
          1. f1(A,B,C,D) -> f1(A,A,0,D)     [B >= E && A = B]               (?,1)
          2. f1(A,B,C,D) -> f1(1 + A,A,E,D) [0 >= 1 + E && B >= F && A = B] (?,1)
          3. f1(A,B,C,D) -> f1(1 + A,A,E,D) [E >= 1 && B >= F && A = B]     (?,1)
          4. f1(A,B,C,D) -> f1(A,B,0,D)     [B >= 1 + A]                    (?,1)
          5. f1(A,B,C,D) -> f1(1 + A,B,E,D) [0 >= 1 + E && B >= 1 + A]      (?,1)
          6. f1(A,B,C,D) -> f1(1 + A,B,E,D) [E >= 1 && B >= 1 + A]          (?,1)
          7. f2(A,B,C,D) -> f1(A,B,C,D)     True                            (1,1)
        Signature:
          {(f1,4);(f2,4);(f300,4)}
        Flow Graph:
          [0->{},1->{0,1,2,3,4,5,6},2->{0,1,2,3,4,5,6},3->{0,1,2,3,4,5,6},4->{0,1,2,3,4,5,6},5->{0,1,2,3,4,5,6}
          ,6->{0,1,2,3,4,5,6},7->{0,1,2,3,4,5,6}]
        
    + Applied Processor:
        TrivialSCCs
    + Details:
        All trivial SCCs of the transition graph admit timebound 1.
* Step 2: UnsatPaths MAYBE
    + Considered Problem:
        Rules:
          0. f1(A,B,C,D) -> f300(A,B,C,E)   [A >= B && A >= 1 + B]          (1,1)
          1. f1(A,B,C,D) -> f1(A,A,0,D)     [B >= E && A = B]               (?,1)
          2. f1(A,B,C,D) -> f1(1 + A,A,E,D) [0 >= 1 + E && B >= F && A = B] (?,1)
          3. f1(A,B,C,D) -> f1(1 + A,A,E,D) [E >= 1 && B >= F && A = B]     (?,1)
          4. f1(A,B,C,D) -> f1(A,B,0,D)     [B >= 1 + A]                    (?,1)
          5. f1(A,B,C,D) -> f1(1 + A,B,E,D) [0 >= 1 + E && B >= 1 + A]      (?,1)
          6. f1(A,B,C,D) -> f1(1 + A,B,E,D) [E >= 1 && B >= 1 + A]          (?,1)
          7. f2(A,B,C,D) -> f1(A,B,C,D)     True                            (1,1)
        Signature:
          {(f1,4);(f2,4);(f300,4)}
        Flow Graph:
          [0->{},1->{0,1,2,3,4,5,6},2->{0,1,2,3,4,5,6},3->{0,1,2,3,4,5,6},4->{0,1,2,3,4,5,6},5->{0,1,2,3,4,5,6}
          ,6->{0,1,2,3,4,5,6},7->{0,1,2,3,4,5,6}]
        
    + Applied Processor:
        UnsatPaths
    + Details:
        We remove following edges from the transition graph: [(1,0)
                                                             ,(1,4)
                                                             ,(1,5)
                                                             ,(1,6)
                                                             ,(2,1)
                                                             ,(2,2)
                                                             ,(2,3)
                                                             ,(2,4)
                                                             ,(2,5)
                                                             ,(2,6)
                                                             ,(3,1)
                                                             ,(3,2)
                                                             ,(3,3)
                                                             ,(3,4)
                                                             ,(3,5)
                                                             ,(3,6)
                                                             ,(4,0)
                                                             ,(4,1)
                                                             ,(4,2)
                                                             ,(4,3)
                                                             ,(5,0)
                                                             ,(6,0)]
* Step 3: AddSinks MAYBE
    + Considered Problem:
        Rules:
          0. f1(A,B,C,D) -> f300(A,B,C,E)   [A >= B && A >= 1 + B]          (1,1)
          1. f1(A,B,C,D) -> f1(A,A,0,D)     [B >= E && A = B]               (?,1)
          2. f1(A,B,C,D) -> f1(1 + A,A,E,D) [0 >= 1 + E && B >= F && A = B] (?,1)
          3. f1(A,B,C,D) -> f1(1 + A,A,E,D) [E >= 1 && B >= F && A = B]     (?,1)
          4. f1(A,B,C,D) -> f1(A,B,0,D)     [B >= 1 + A]                    (?,1)
          5. f1(A,B,C,D) -> f1(1 + A,B,E,D) [0 >= 1 + E && B >= 1 + A]      (?,1)
          6. f1(A,B,C,D) -> f1(1 + A,B,E,D) [E >= 1 && B >= 1 + A]          (?,1)
          7. f2(A,B,C,D) -> f1(A,B,C,D)     True                            (1,1)
        Signature:
          {(f1,4);(f2,4);(f300,4)}
        Flow Graph:
          [0->{},1->{1,2,3},2->{0},3->{0},4->{4,5,6},5->{1,2,3,4,5,6},6->{1,2,3,4,5,6},7->{0,1,2,3,4,5,6}]
        
    + Applied Processor:
        AddSinks
    + Details:
        ()
* Step 4: UnsatPaths MAYBE
    + Considered Problem:
        Rules:
          0. f1(A,B,C,D) -> f300(A,B,C,E)      [A >= B && A >= 1 + B]          (?,1)
          1. f1(A,B,C,D) -> f1(A,A,0,D)        [B >= E && A = B]               (?,1)
          2. f1(A,B,C,D) -> f1(1 + A,A,E,D)    [0 >= 1 + E && B >= F && A = B] (?,1)
          3. f1(A,B,C,D) -> f1(1 + A,A,E,D)    [E >= 1 && B >= F && A = B]     (?,1)
          4. f1(A,B,C,D) -> f1(A,B,0,D)        [B >= 1 + A]                    (?,1)
          5. f1(A,B,C,D) -> f1(1 + A,B,E,D)    [0 >= 1 + E && B >= 1 + A]      (?,1)
          6. f1(A,B,C,D) -> f1(1 + A,B,E,D)    [E >= 1 && B >= 1 + A]          (?,1)
          7. f2(A,B,C,D) -> f1(A,B,C,D)        True                            (1,1)
          8. f1(A,B,C,D) -> exitus616(A,B,C,D) True                            (?,1)
        Signature:
          {(exitus616,4);(f1,4);(f2,4);(f300,4)}
        Flow Graph:
          [0->{},1->{0,1,2,3,4,5,6,8},2->{0,1,2,3,4,5,6,8},3->{0,1,2,3,4,5,6,8},4->{0,1,2,3,4,5,6,8},5->{0,1,2,3,4,5
          ,6,8},6->{0,1,2,3,4,5,6,8},7->{0,1,2,3,4,5,6,8},8->{}]
        
    + Applied Processor:
        UnsatPaths
    + Details:
        We remove following edges from the transition graph: [(1,0)
                                                             ,(1,4)
                                                             ,(1,5)
                                                             ,(1,6)
                                                             ,(2,1)
                                                             ,(2,2)
                                                             ,(2,3)
                                                             ,(2,4)
                                                             ,(2,5)
                                                             ,(2,6)
                                                             ,(3,1)
                                                             ,(3,2)
                                                             ,(3,3)
                                                             ,(3,4)
                                                             ,(3,5)
                                                             ,(3,6)
                                                             ,(4,0)
                                                             ,(4,1)
                                                             ,(4,2)
                                                             ,(4,3)
                                                             ,(5,0)
                                                             ,(6,0)]
* Step 5: Failure MAYBE
  + Considered Problem:
      Rules:
        0. f1(A,B,C,D) -> f300(A,B,C,E)      [A >= B && A >= 1 + B]          (?,1)
        1. f1(A,B,C,D) -> f1(A,A,0,D)        [B >= E && A = B]               (?,1)
        2. f1(A,B,C,D) -> f1(1 + A,A,E,D)    [0 >= 1 + E && B >= F && A = B] (?,1)
        3. f1(A,B,C,D) -> f1(1 + A,A,E,D)    [E >= 1 && B >= F && A = B]     (?,1)
        4. f1(A,B,C,D) -> f1(A,B,0,D)        [B >= 1 + A]                    (?,1)
        5. f1(A,B,C,D) -> f1(1 + A,B,E,D)    [0 >= 1 + E && B >= 1 + A]      (?,1)
        6. f1(A,B,C,D) -> f1(1 + A,B,E,D)    [E >= 1 && B >= 1 + A]          (?,1)
        7. f2(A,B,C,D) -> f1(A,B,C,D)        True                            (1,1)
        8. f1(A,B,C,D) -> exitus616(A,B,C,D) True                            (?,1)
      Signature:
        {(exitus616,4);(f1,4);(f2,4);(f300,4)}
      Flow Graph:
        [0->{},1->{1,2,3,8},2->{0,8},3->{0,8},4->{4,5,6,8},5->{1,2,3,4,5,6,8},6->{1,2,3,4,5,6,8},7->{0,1,2,3,4,5,6
        ,8},8->{}]
      
  + Applied Processor:
      LooptreeTransformer
  + Details:
      We construct a looptree:
        P: [0,1,2,3,4,5,6,7,8]
        |
        +- p:[4,5,6] c: [6]
        |  |
        |  `- p:[4,5] c: [5]
        |     |
        |     `- p:[4] c: []
        |
        `- p:[1] c: []
MAYBE