# Other questions and answers in March 2021 — Page 13

Work over the universal set U = {1,2,3,4,5}. Let Ao = {{1,2,3}, {3,4,5}}. For each n E Zoo, define An+ 1 = { X n Y : X, Y E An } U { XUY : X,YEA, JU { X : XEAn). a) Write down in roster notation all ...