A={(X,Y)|(1.2),(1.4),(1.6),(2.1).(2.3).(2.5).(3.1).(3.4).(3.6).(4.1).(4.3)(4.5)(5.2)(5.4).(5.6).(6.1).(6.3).(6.5)};
B={(X,Y)|(1.1).(2.2).(3.3).(4.4).(5.5).(6.6)};
C={(X,Y)|(1.1)(1.2)(1.3)(1.4)(1.5)(1.6)(2.1)(2.2)(2.3)(2.4)(2.5)(2.6)(3.1)(3.2)(3.3)(3.4)(3.5)(3.6)(4.1)(4.2)(4.3)(4.4)(4.5)(5.1)(5.2)(5.3)(5.4)(6.1)(6.2)(6.3)};
B-A=B;
BC={(X,Y)|(1.1).(2.2).(3.3).(4.4)};
B+C={(X,Y)|(1.1)(1.2)(1.3)(1.4)(1.5)(1.6)(2.1)(2.2)(2.3)(2.4)(2.5)(2.6)(3.1)(3.2)(3.3)(3.4)(3.5)(3.6)(4.1)(4.2)(4.3)(4.4)(4.5)(5.1)(5.2)(5.3)(5.4)(6.1)(6.2)(6.3)(5.5)(6.6)};
式中"."都代表“,”,括号与括号之间的逗号也都没加了,自己加上了.