Let X={1,2,3}X={1,2,3}. Let P(X)P(X) be the set of all subsets of XX (i.e. Power set of XX). Let RR be a relation defined on P(X)P(X) by the following. For all sets AA and BB in P(X)P(X), ARBARB iff |A|=|B||A|=|B|. Is RR an equivalence relation?