Herstein: Homomorphism Proof

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In summary, we need to prove that if φ is a homomorphism of G onto G' and N is a normal subgroup of G, then φ(N) is also a normal subgroup of G. To do this, we can use the fact that φ is onto, meaning that every element in G' is the image of some element in G. Then, by using the properties of homomorphisms, we can show that kφ(n)k-1 = φ(N), which proves that φ(N) is indeed a normal subgroup of G.
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ThatPinkSock
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From Herstein's Abstract Algebra. Section 2.7 #7



If φ is a homomorphism of G onto G' and N ◅ G, show that φ(N) ◅ G.



Attempt:
I want to prove that if k ∈ G' then kφ(N)k-1 = φ(N), but k = φ(n) for some n... then idk what.
 
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  • #2
Take a in N, you need to prove that

[tex]k\varphi(a)k^{-1}\in \varphi(N)[/tex]

Replace k with [itex]\varphi(n)[/itex], what do you get??
 
  • #3
the fact that φ is onto is important.

this means that EVERY k in G' is the image of some g in G:

k = φ(g). now use the fact that φ is a homomorphism.

what can we say about kφ(n)k-1?
 

What is a homomorphism?

A homomorphism is a function between two algebraic structures that preserves the operations of the structures. In other words, it maps elements from one structure to another in a way that respects the algebraic operations.

What is the significance of Homomorphism Proof in mathematics?

Homomorphism Proof is significant in mathematics because it allows for the study of the relationships between different algebraic structures. It also helps to establish a connection between seemingly unrelated structures and can reveal hidden similarities and patterns.

How is Homomorphism Proof used in abstract algebra?

In abstract algebra, Homomorphism Proof is used to show that a function between two algebraic structures is a homomorphism. This is useful in proving theorems and properties of algebraic structures, such as groups, rings, and fields.

What is the process of proving a function is a homomorphism?

The process of proving a function is a homomorphism involves showing that the function preserves the algebraic operations of the structures. This is typically done by showing that the function satisfies the necessary properties, such as the preservation of identity and the operation of the structures.

What are some applications of Homomorphism Proof in other fields?

Homomorphism Proof has applications in various fields, such as computer science, cryptography, and physics. In computer science, it is used in the design and analysis of algorithms. In cryptography, it is used to ensure the security of encrypted messages. In physics, it is used in the study of symmetries and conservation laws.

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