MAYBE

Problem:
 a(a(x1)) -> b(b(b(x1)))
 b(b(x1)) -> c(c(c(x1)))
 c(c(x1)) -> d(d(d(x1)))
 b(x1) -> d(d(x1))
 c(d(d(x1))) -> a(x1)

Proof:
 Complexity Transformation Processor:
  strict:
   a(a(x1)) -> b(b(b(x1)))
   b(b(x1)) -> c(c(c(x1)))
   c(c(x1)) -> d(d(d(x1)))
   b(x1) -> d(d(x1))
   c(d(d(x1))) -> a(x1)
  weak:
   
  Matrix Interpretation Processor:
   dimension: 1
   max_matrix:
    1
    interpretation:
     [d](x0) = x0 + 1,
     
     [c](x0) = x0,
     
     [b](x0) = x0,
     
     [a](x0) = x0
    orientation:
     a(a(x1)) = x1 >= x1 = b(b(b(x1)))
     
     b(b(x1)) = x1 >= x1 = c(c(c(x1)))
     
     c(c(x1)) = x1 >= x1 + 3 = d(d(d(x1)))
     
     b(x1) = x1 >= x1 + 2 = d(d(x1))
     
     c(d(d(x1))) = x1 + 2 >= x1 = a(x1)
    problem:
     strict:
      a(a(x1)) -> b(b(b(x1)))
      b(b(x1)) -> c(c(c(x1)))
      c(c(x1)) -> d(d(d(x1)))
      b(x1) -> d(d(x1))
     weak:
      c(d(d(x1))) -> a(x1)
    Matrix Interpretation Processor:
     dimension: 1
     max_matrix:
      1
      interpretation:
       [d](x0) = x0,
       
       [c](x0) = x0 + 1,
       
       [b](x0) = x0,
       
       [a](x0) = x0
      orientation:
       a(a(x1)) = x1 >= x1 = b(b(b(x1)))
       
       b(b(x1)) = x1 >= x1 + 3 = c(c(c(x1)))
       
       c(c(x1)) = x1 + 2 >= x1 = d(d(d(x1)))
       
       b(x1) = x1 >= x1 = d(d(x1))
       
       c(d(d(x1))) = x1 + 1 >= x1 = a(x1)
      problem:
       strict:
        a(a(x1)) -> b(b(b(x1)))
        b(b(x1)) -> c(c(c(x1)))
        b(x1) -> d(d(x1))
       weak:
        c(c(x1)) -> d(d(d(x1)))
        c(d(d(x1))) -> a(x1)
      Matrix Interpretation Processor:
       dimension: 1
       max_matrix:
        1
        interpretation:
         [d](x0) = x0,
         
         [c](x0) = x0,
         
         [b](x0) = x0 + 1,
         
         [a](x0) = x0
        orientation:
         a(a(x1)) = x1 >= x1 + 3 = b(b(b(x1)))
         
         b(b(x1)) = x1 + 2 >= x1 = c(c(c(x1)))
         
         b(x1) = x1 + 1 >= x1 = d(d(x1))
         
         c(c(x1)) = x1 >= x1 = d(d(d(x1)))
         
         c(d(d(x1))) = x1 >= x1 = a(x1)
        problem:
         strict:
          a(a(x1)) -> b(b(b(x1)))
         weak:
          b(b(x1)) -> c(c(c(x1)))
          b(x1) -> d(d(x1))
          c(c(x1)) -> d(d(d(x1)))
          c(d(d(x1))) -> a(x1)
        Open