Is Group G Abelian if f(a)=a^-1 is a Homomorphism?

  • Thread starter ldelong
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In summary, to prove that a Group G is abelian, it must be shown that the function f:G to G given by f(a)=a^-1 is a homomorphism. This means that for any elements a and b in G, f(ab) = f(a)f(b). Since the condition for f to be a homomorphism is f(ab) = f(a)f(b), the commutativity of the group must be utilized. By plugging in the definition of f at the right points, it can be shown that Group G is abelian if the function f is a homomorphism.
  • #1
ldelong
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Homework Statement


Prove that Group G is abelian iff the function f:G to G given by f(a)=a^-1 is a homomorphism

Homework Equations





The Attempt at a Solution



Group G must be communitative for it to be abelian I have no idea where to start to begin to prove this I know that homomorphic means that complete the operation first on a in the group gets mapped to an element that the operation is completed 2nd. Help... I really need a jumping point.
 
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  • #2
You can start by writing out some relevant definitions and basic facts along with the facts you're given. Often this is also where you finish. In this case, remember that the condition for f to be a homomorphism is f(ab)=f(a)f(b). Now use the definition of f.
 
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  • #3
ldelong said:
Group G must be communitative for it to be abelian


When I see things like that I worry. Commutative and abelian are synonyms.
 
  • #4
Actually there's not much to prove. It is, as StatusX already said, a matter of writing out the definition of homeomorphism and plugging in commutativity of the group and the definition of f at the right points.

So just start writing something down, then tell us where you get stuck.
 
  • #5
I got it thanks
 

What is a homomorphism?

A homomorphism is a mathematical function that preserves the structure of a group or algebraic structure, meaning that the operation being performed on the elements of the structure is preserved by the function.

What does it mean for a homomorphism to be abelian?

A homomorphism is abelian if the order in which the elements are multiplied does not affect the outcome of the operation. This means that the function commutes, or that the elements can be rearranged without changing the result.

How does a homomorphism help in understanding algebraic structures?

Homomorphisms help in understanding algebraic structures by showing the relationships between different structures and how they are related through their underlying operations. They also help in identifying isomorphisms, which are structures that are essentially the same, even though they may have different representations.

What are some common examples of homomorphisms?

Some common examples of homomorphisms include the logarithmic function, which preserves multiplication, and the absolute value function, which preserves addition. Another example is the determinant function in linear algebra, which preserves the matrix multiplication operation.

How can homomorphisms be used in practical applications?

Homomorphisms have many practical applications, especially in cryptography and coding theory. They can be used to encrypt data by transforming it into a different mathematical structure, making it difficult to decipher without the proper key. They can also be used to detect errors in data transmission, as any changes to the data will result in a different value after the homomorphism is applied.

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