Proving Isomorphism of Z4 / (2Z4) and Z2

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In summary, the conversation discusses forming the factor group Z4/(2Z4) and how it is isomorphic to Z2. The quotient group exists because 2Z4 is a normal subgroup of Z4, and to prove the isomorphism, one must list the elements of Z4/2Z4 and write down the isomorphism. It is then important to prove that the isomorphism has the necessary properties. The final question is how many elements are in Z4/2Z4 and how many groups have the same number of elements.
  • #1
DanielThrice
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Homework Statement


Why does it make sense (when considering Z4)to form the factor group

Z4 / (2Z4) where kZn = {0, k mod n, 2k mod n, ..., nk mod n}?

I believe that this above factor group is isomorphic to Z2, but how can I prove this?
 
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  • #2
The quotient group exists because 2Z4 is a normal subgroup of Z4 (since Z4 is abelian, all its subgroups are normal). To show that it is isomorphic to Z2, list the elements of Z4/2Z4 (which are cosets), and write down the isomorphism. Then, prove what you have is indeed an isomorphism, i.e. that it has the properties of an isomorphism.
 
  • #3
How many elements are in Z4/2Z4? How many groups have that many elements?
 

Related to Proving Isomorphism of Z4 / (2Z4) and Z2

1. What is the definition of isomorphism?

Isomorphism is a mathematical concept that describes a relationship between two structures that have the same underlying structure or properties. In other words, two structures are isomorphic if they have the same shape or structure, even if their individual elements may be different.

2. How do you prove isomorphism between two structures?

In order to prove isomorphism between two structures, you need to show that there is a function, called an isomorphism, that maps one structure to the other while preserving the structure and properties of the original structure. This function must be bijective, meaning that it is both one-to-one and onto.

3. What is the relationship between Z4 / (2Z4) and Z2?

Z4 / (2Z4) and Z2 are both mathematical structures known as quotient groups. Z4 / (2Z4) is the set of all possible cosets (or subsets) of Z4 that are formed by dividing Z4 by the subgroup 2Z4. Z2, on the other hand, is the set of all possible remainders when dividing Z4 by 2. These two structures are isomorphic, meaning they have the same underlying structure.

4. How can you prove isomorphism between Z4 / (2Z4) and Z2?

In order to prove isomorphism between Z4 / (2Z4) and Z2, you need to show that there is a bijective function between the two structures. One way to do this is by constructing a mapping between the elements of Z4 / (2Z4) and Z2, and then showing that this mapping is both one-to-one and onto.

5. Why is proving isomorphism between Z4 / (2Z4) and Z2 important?

Proving isomorphism between Z4 / (2Z4) and Z2 is important because it helps us to better understand the underlying structure and properties of these mathematical structures. It also allows us to simplify complex structures into more easily understandable ones, and can be useful in solving various mathematical problems and equations.

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