Isomorphism of A(Zn) and Zn/{0}: A Proof

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In summary, the conversation discusses the definition of A(G) as the set of isomorphisms from a group G to itself, and the proof that A(G) is a group under composition. It also poses two problems, one regarding the isomorphism of A(Zn) and Zn/{0}, and the other regarding the isomorphism of A(Z) and Z2. The conversation also explores the concept of automorphisms and provides examples of them.
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Homework Statement



Recall that given a group G, we defined A(G) to be the set of all isomorphisms from G to itself; you proved that A(G) is a group under composition.
(a) Prove that A(Zn) is isomorphic to Zn/{0}
(b) Prove that A(Z) is isomorphic to Z2

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The Attempt at a Solution

 
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There aren't very many automorphisms of Z->Z. In fact, I think there is only two of them. For the other question, I'm not really sure what Z_n/{0} means. Can you explain?
 
  • #3
Can you figure out the sets A(Zn) and A(Z)?
The identity function is one that should come to mind.
Take a general function on Z by f(x)=bx for some b in Z. What values can b take on so that f(x) is a bijection?
 

FAQ: Isomorphism of A(Zn) and Zn/{0}: A Proof

What does it mean for two groups to be isomorphic?

Two groups are isomorphic if there exists a bijective mapping (or function) between the elements of the two groups that preserves the group structure and operations.

How do you prove that two groups are isomorphic?

To prove that two groups are isomorphic, you must show that there exists a bijective mapping between their elements that preserves the group structure and operations. This can be done by constructing an isomorphism, which is a function that satisfies these conditions, or by showing that all elements of one group can be uniquely mapped to elements of the other group.

What are some properties of isomorphic groups?

Isomorphic groups have the same size or cardinality, the same group structure (e.g. commutativity, associativity, identity element), and the same group operations (e.g. multiplication, addition, exponentiation).

Can two groups be isomorphic but have different names or notations?

Yes, two groups can be isomorphic even if they have different names or notations. Isomorphism is a concept that focuses on the structure and operations of the groups, not their names or symbols.

How does proving groups are isomorphic help in mathematical research?

Proving groups are isomorphic allows for the translation and transfer of knowledge between different groups. This can help in identifying patterns, solving problems, and making connections between seemingly unrelated groups. It also allows for the generalization of results from one group to another.

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