= 3. Let m € N and a € Z, and let a = a +mZ. Prove that a € (Z/mZ)× if and only if ged(a,m) 1. (Hint: Explain why the ex
Posted: Wed May 04, 2022 11:03 am
= 3. Let m € N and a € Z, and let a = a +mZ. Prove that a € (Z/mZ)× if and only if ged(a,m) 1. (Hint: Explain why the existence of an inverse for a is equivalent to the existence of an integer b € Z such that ab = 1 (mod m). Bézout's lemma can help with the proof of the "if" statement.)