Need help checking a proof on a cyclic group

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SUMMARY

The discussion centers on proving that the group of rational numbers (Q, +) is not cyclic. The proof presented uses a contradiction approach, assuming that (Q, +) can be generated by a single element p/q, where q ≠ 0. The conclusion drawn is that since p/(2q) cannot be expressed as k(p/q) for any integer k, (Q, +) cannot be cyclic. This proof is validated by the participants, confirming its correctness and thoroughness.

PREREQUISITES
  • Understanding of group theory concepts, specifically cyclic groups.
  • Familiarity with the properties of rational numbers and their operations.
  • Knowledge of proof techniques, particularly proof by contradiction.
  • Basic comprehension of integer sets and their properties.
NEXT STEPS
  • Study the properties of cyclic groups in group theory.
  • Explore the implications of the structure of (Q, +) in abstract algebra.
  • Learn about other non-cyclic groups and their characteristics.
  • Investigate proof techniques in mathematics, focusing on contradiction and direct proofs.
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Mathematics students, particularly those studying abstract algebra, group theory enthusiasts, and educators looking to deepen their understanding of cyclic and non-cyclic groups.

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1. Prove that (Q,+) is not cyclic



Here is what I have, and I need help knowing if this proof makes sense, is thorough enough, or is completely wrong. Note that (Q,+) is rationals

Suppose, by contradiction, that (Q,+) is cyclic, p/q E (Q,+) and q=/=0
=> (Q,+) can be generated by <p/q> = {k(p/q)|k E Z}
if p/(2q) E (Q,+)
then p/(2q) can be generated by k(p/q)
=> p/(2q)=k(p/q)
1/2=k
therefore k does not belong to Z and (Q,+) is not cyclic

It seems like I am missing something or made a conceptual error somewhere. Any help or confirmation is appreciated.
 
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