Maximal normal subgroups proof

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SUMMARY

The discussion centers on proving that a subgroup M is a maximal normal subgroup of a group G if and only if the quotient group G/M is simple. The proof involves utilizing the isomorphism theorem, which establishes a bijection between subgroups containing a normal subgroup H and the subgroups of H. The conclusion drawn is that if G/M is simple, then any proper normal subgroup of G/M leads to a contradiction regarding the normal subgroup structure of G.

PREREQUISITES
  • Understanding of group theory concepts, specifically normal subgroups.
  • Familiarity with the isomorphism theorem in group theory.
  • Knowledge of group homomorphisms and their properties.
  • Basic comprehension of quotient groups and their significance in group theory.
NEXT STEPS
  • Study the isomorphism theorem in detail to understand its implications in group theory.
  • Explore the properties of simple groups and their classification.
  • Learn about maximal subgroups and their characteristics in various group structures.
  • Investigate examples of normal subgroups in specific groups, such as symmetric groups or abelian groups.
USEFUL FOR

This discussion is beneficial for students and researchers in abstract algebra, particularly those studying group theory, as well as educators looking for examples of maximal normal subgroups and their proofs.

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Homework Statement


Prove that M is a maximal normal subgroup of G if and only G/M is simple

Homework Equations


The Attempt at a Solution


This is what I have so far.
Let f:G----> G/M be a group homomorphism with M a maximal normal subgroup of G. Suppose there exist a proper normal subgroup H of G/M
But then this would imply that f^(-1)(H) is a proper normal subgroup of G containing M which is contrary to assumption.

I am guessing the reverse goes something like suppose g: G/M---> G is a group homomorphism and suppose G/M is simple.
But then I am kind of stuck

Can anyone help?
 
Last edited:
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no one can help...
 
Do you know the isomorphism theorem (one of the variants), which says that there exists a bijections between subgroups which contain H and subgroups of H? Do you also know that this bijection sends normal subgroups to normal subgroups?

This pretty much solves the question...
 

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