Let (Z, +) denote the group of all integers under addition. Then the number of automorphisms of (Z, +) is
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Correct answer: B. 2
Explanation
An automorphism must send the generator 1 to a generator, i.e. to 1 or −1. So the only automorphisms are x ↦ x and x ↦ −x.More Discrete Structures and Optimisation questions
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