إذا كان
U equals space left curly bracket 1 comma 2 comma space... space comma space 10 right curly bracket A equals left curly bracket 1 comma space 3 comma space 5 comma space 7 comma space 9 right curly bracket B equals left curly bracket 2 comma space 4 comma space 6 comma space 8 comma space 10 right curly bracket
فإن
A minus B equals
A
empty set
U
B