TRS:
 {f(x, y) -> h(x, y),
  f(x, y) -> h(y, x),
  h(x, x) -> x}
 POP* + Boolean Semantic Labelling:
  Normal positions:
  pi(f_sl=1) = [1,2], pi(f_sl=0) = [1,2], pi(h_sl=1) = [1,2], pi(h_sl=0) = [1,2]
  
Safe positions:
   
  
Precedence:
   f_sl=0 > h_sl=0
   empty
  
Interpretation:
   h^(2):
   00 | 0
   01 | 0
   10 | 0
   11 | 1
   f^(2):
   00 | 0
   01 | 0
   10 | 0
   11 | 1
   
  
Labelling:
   h^(2):
   00 | 0
   01 | 0
   10 | 0
   11 | 0
   f^(2):
   00 | 0
   01 | 0
   10 | 0
   11 | 0
   
  
Labelled predicative System:
   {f_sl=0(x,y;) -> h_sl=0(x,y;),
    f_sl=0(x,y;) -> h_sl=0(x,y;),
    f_sl=0(x,y;) -> h_sl=0(x,y;),
    f_sl=0(x,y;) -> h_sl=0(x,y;),
    f_sl=0(x,y;) -> h_sl=0(y,x;),
    f_sl=0(x,y;) -> h_sl=0(y,x;),
    f_sl=0(x,y;) -> h_sl=0(y,x;),
    f_sl=0(x,y;) -> h_sl=0(y,x;),
    h_sl=0(x,x;) -> x,
    h_sl=0(x,x;) -> x}
  

  Qed