, lie in R and no odd integer is related to 0, as (0, ± 1), (0, ± 3) etc , do not lie in R Similarly, all odd integers are related to one and no even integer is related to one Therefore, the set E of all even integers and the set O of all odd integers are subsets of
Z satisfying following conditions:
(i)
All elements of E are related to each other and all elements of O are related to
each other