Examples {emp}×:=cons(1,2){x-1,2} {x一1,2}y=[]{x一1,2∧y=1} {x→1,2Λy=1}[x+1]:=3{x-1,3∧y=1} {x→1,3∧y=1}dispose×{×+1-3∧y=1} {X→-*y一-} if y =x+1 then skip else if x=y+1 then x:=y else (dispose x;dispose y;x:=cons(1,2)) {x一-，-}Examples