“…We use the method of calculating conservation laws described in [12,13], which works as follows. The three-point conservation laws can be determined directly by substituting (1) into F (k+1, l, u 1,0 , u 1,1 )−F (k, l, u 0,0 , u 0,1 )+G(k, l+1, u 0,1 , u 1,1 )−G(k, l, u 0,0 , u 1,0 ) = 0, (4) and solving the resulting functional equation.…”