Theorem 11.5: The group Zm x Zn is cyclic (hence isomorphic to Zmn) if and only if gcd(m, n) = 1.
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It's saying that the direct product of the groups Zm and Zn is cyclic (meaning it can be generated by a single element) if and only if the greatest common divisor (gcd) of m and n is 1. Now, let's prove this theorem. (=>) Suppose that Zm x Zn is cyclic. Let (a, Show more…
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