MAYBE

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

Proof:
 RT Transformation Processor:
  strict:
   a(x1) -> x1
   a(a(b(b(x1)))) -> b(c(a(c(x1))))
   c(x1) -> b(a(x1))
  weak:
   
  Matrix Interpretation Processor:
   dimension: 1
   interpretation:
    [c](x0) = x0 + 1,
    
    [b](x0) = x0 + 5,
    
    [a](x0) = x0 + 4
   orientation:
    a(x1) = x1 + 4 >= x1 = x1
    
    a(a(b(b(x1)))) = x1 + 18 >= x1 + 11 = b(c(a(c(x1))))
    
    c(x1) = x1 + 1 >= x1 + 9 = b(a(x1))
   problem:
    strict:
     c(x1) -> b(a(x1))
    weak:
     a(x1) -> x1
     a(a(b(b(x1)))) -> b(c(a(c(x1))))
   Open