1.* Infinite sums and infinite products of cardinals are defined as follows: Let d; be cardinals, and pick D, with o(D;)
Posted: Mon Jul 11, 2022 12:14 pm
1.* Infinite sums and infinite products of cardinals are defined as follows: Let d; be cardinals, and pick D, with o(D;) = d;. (For Ed, pick the Dis disjoint.) Then Ed; is the cardinal of U Dā, and II d; is the cardinal of the Cartesian product of the Di's. Let di, e; be cardinals with d; < e, for all i. Prove that Ed; < Ile;. (Observe that if every d; = 1 and every e; = 2 we get Theorem 6.) 2.* Prove that N > N. (Hint: By Exercise 1 we have Nā... No + N + ...+ā+... < NON The left side is No; the right side ⤠No.) 3.* Prove that c N. (Hint: Use Exercise 2.)