Showing the uniqueness of the group of integers

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SUMMARY

The infinite cyclic group Z is the unique group that is isomorphic to all its non-trivial proper subgroups. This is established by demonstrating that every subgroup of Z is cyclic and can be expressed in the form mZ, where m is greater than or equal to 2. The isomorphism between Z and its subgroups is straightforward to prove. To assert the uniqueness of Z, one can assume the existence of two distinct infinite cyclic groups isomorphic to their respective non-trivial proper subgroups and derive a contradiction through the construction of an isomorphism.

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  • Understanding of cyclic groups and their properties
  • Familiarity with group isomorphisms
  • Basic knowledge of subgroup structures
  • Experience with mathematical proof techniques
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  • Study the properties of cyclic groups in group theory
  • Learn about group isomorphisms and their applications
  • Explore examples of infinite cyclic groups and their subgroups
  • Investigate proof techniques in abstract algebra
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Mathematics students, particularly those studying abstract algebra, group theory enthusiasts, and educators looking to deepen their understanding of cyclic groups and isomorphism concepts.

playa007
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Homework Statement


Show that the infinite cyclic group Z is the unique group that is isomorphic to all its non-trivial proper subgroups


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The Attempt at a Solution


Due to the fact that Z is cyclic and that every subgroup is a cyclic group, every subgroup of Z is a cyclic group, precisely of the form mZ (where m=>2); and the isomorphism between the two groups is not difficult to show. But I'm wondering how to assert uniqueness that Z is indeed the unique group?
 
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hi playa007, to be honest I've only had limited exposure to groups, so not sure... but as an idea could you assume you have two different infinite cyclic groups isomorphic to their respective non-trivial proper subgroups, then construct an isomorphism to give a contradiction and show they are in fact the same (unique) group?
 
Well, you could start by trying some specific examples, to get some ideas.
 

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