YES(?,O(n^2))

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

Proof:
 Matrix Interpretation Processor:
  dimension: 2
  interpretation:
             [1 1]  
   [b](x0) = [0 1]x0,
   
             [1 1]     [4]
   [a](x0) = [0 1]x0 + [1]
  orientation:
             [1 2]    [9]    [1 2]           
   a(a(x)) = [0 1]x + [2] >= [0 1]x = b(b(x))
   
                [1 3]    [6]    [1 3]    [4]             
   b(b(a(x))) = [0 1]x + [1] >= [0 1]x + [1] = a(b(b(x)))
  problem:
   
  Qed