YES(?,O(n^2))

Problem:
 rev(ls) -> r1(ls,empty())
 r1(empty(),a) -> a
 r1(cons(x,k),a) -> r1(k,cons(x,a))

Proof:
 RT Transformation Processor:
  strict:
   rev(ls) -> r1(ls,empty())
   r1(empty(),a) -> a
   r1(cons(x,k),a) -> r1(k,cons(x,a))
  weak:
   
  Matrix Interpretation Processor:
   dimension: 1
   interpretation:
    [cons](x0, x1) = x0 + x1 + 14,
    
    [r1](x0, x1) = x0 + x1 + 20,
    
    [empty] = 0,
    
    [rev](x0) = x0 + 24
   orientation:
    rev(ls) = ls + 24 >= ls + 20 = r1(ls,empty())
    
    r1(empty(),a) = a + 20 >= a = a
    
    r1(cons(x,k),a) = a + k + x + 34 >= a + k + x + 34 = r1(k,cons(x,a))
   problem:
    strict:
     r1(cons(x,k),a) -> r1(k,cons(x,a))
    weak:
     rev(ls) -> r1(ls,empty())
     r1(empty(),a) -> a
   Matrix Interpretation Processor:
    dimension: 2
    interpretation:
                      [1 8]          [0]
     [cons](x0, x1) = [0 0]x0 + x1 + [2],
     
                    [1 1]          [11]
     [r1](x0, x1) = [0 1]x0 + x1 + [0 ],
     
               [1]
     [empty] = [0],
     
                 [1 2]     [14]
     [rev](x0) = [0 1]x0 + [1 ]
    orientation:
                           [1 1]    [1 8]    [13]        [1 1]    [1 8]    [11]                  
     r1(cons(x,k),a) = a + [0 1]k + [0 0]x + [2 ] >= a + [0 1]k + [0 0]x + [2 ] = r1(k,cons(x,a))
     
               [1 2]     [14]    [1 1]     [12]                 
     rev(ls) = [0 1]ls + [1 ] >= [0 1]ls + [0 ] = r1(ls,empty())
     
                         [12]         
     r1(empty(),a) = a + [0 ] >= a = a
    problem:
     strict:
      
     weak:
      r1(cons(x,k),a) -> r1(k,cons(x,a))
      rev(ls) -> r1(ls,empty())
      r1(empty(),a) -> a
    Qed