MAYBE

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

Proof:
 RT Transformation Processor:
  strict:
   a(a(a(a(x1)))) -> b(a(a(a(x1))))
   b(b(x1)) -> a(a(b(x1)))
  weak:
   
  Matrix Interpretation Processor:
   dimension: 1
   interpretation:
    [b](x0) = x0 + 16,
    
    [a](x0) = x0 + 1
   orientation:
    a(a(a(a(x1)))) = x1 + 4 >= x1 + 19 = b(a(a(a(x1))))
    
    b(b(x1)) = x1 + 32 >= x1 + 18 = a(a(b(x1)))
   problem:
    strict:
     a(a(a(a(x1)))) -> b(a(a(a(x1))))
    weak:
     b(b(x1)) -> a(a(b(x1)))
   Open