שינויים

*<math>(x_1,y_1)\sim (x_2,y_2)\iff |x_1|+|y_1|=|x_2|+|y_2|</math>.

*<math>(x_1,y_1)\sim (x_2,y_2)\iff x_1^2-y_1=x_2^2-y_2</math>.

*<math>(x_1,y_1)\sim (x_2,y_2)\iff 5x_1^2-y_1=5x_2^2-y_2</math>.