Hint for Section 10.5 Question 5

5. Let A = {1, 2, 3, 4} and define the relation r on the power set of A,  P(A), as follows: for X, Yin.jpg (595 bytes)P(A),
X r Y iff.jpg (642 bytes)X Ì Y  or  X = Y.
To show that r is a partial order relation, you will need to show that r is reflexive, antisymmetric and transitive. 

Reflexive: For every X in the P(A), is X r X?
Antisymmetric: For all distinct elements X and Y of P(A), if X rY, does this imply that Y is not related to X?
Transtive: For all elements X, Y and Z of P(A), if X r Y and Y r Z, does this imply that X r Z?

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