We now consider a few examples of systems that form groups (or do not form groups). bxample 1: the set z of integers forms an abelian group w.r.t. the usual add

we now consider a few examples of systems that form groups (or do not form groups). BXample 1: The set Z of integers forms an abelian group w.r.t. the usual addition of integers. lt is easy to verify the postulates in the definition of a group as sum of two integers 1S a unique integer (thuc loc