In 22—29, find all greatest, least, maximal, and minimal elements for the relations in each of the referenced exercises.

26. Exercise 18

To find the greatest, least, maximal and minimal elements for the relations in the given exercise.

Given information:

Let S={0,1} and consider the partial order relation R defined on S×S, for all ordered pairs (a,b) and (c,d) in S×S ,

(a,b)R(c,d)⇔ Either a<c or both a=c and  b≤d where ≤ denotes “less than or equal to” rational for real numbers