Subgroup of a Quotient is a Quotient of a Subgroup

In summary, the conversation discusses proving the statement that a subgroup of a quotient of a group is also a quotient of a subgroup of the original group. The attempt at a solution involves using the fourth isomorphism theorem to show that the subgroup H is isomorphic to a subgroup of G of the form H/N, and clarifies that the question may be asking for a proof of the fourth isomorphism theorem itself.
  • #1
Szichedelic
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0

Homework Statement



I'm trying to prove the statement "Show that a subgroup of a quotient of G is also a quotient of a subgroup of G."

Homework Equations



See below.

The Attempt at a Solution



Let G be a group and N be a normal subgroup of G. Let H be a subgroup of the quotient G/N. Then, by the fourth isomorphism theorem, H is isomorphic to the subgroup of G of the form H/N.

I'm wondering if I am done at this point... My teacher's statement is somewhat vague and I can't decide if by "quotient of a subgroup of G," he means G quotiented by ANOTHER normal subgroup or a quotient OF a subgroup of G. If it is the latter, than this problem is trivially true by the fourth isomorphism theorem.
 
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  • #2
I think your approach is fine.
 
  • #3
The question is literally asking you to prove part of the fourth isomorphism theorem, so if you're allowed to cite the relevant part then you're done, but I would double check the context of the question (when it came up in the class, what it says on the homework assignment elsewhere) to see if you're allowed to use that theorem or are supposed to be proving the fourth isomorphism theorem.
 

FAQ: Subgroup of a Quotient is a Quotient of a Subgroup

What does "Subgroup of a Quotient is a Quotient of a Subgroup" mean?

This statement refers to a mathematical concept in group theory, where a subgroup of a quotient group can also be considered as a quotient group of a subgroup. In simpler terms, it means that a subgroup can be formed by taking a quotient group and then finding a subgroup within it.

What is a subgroup?

A subgroup is a subset of a group that satisfies all of the group's properties. In other words, it is a smaller group that is contained within a larger group and follows the same rules and operations.

What is a quotient group?

A quotient group, also known as a factor group, is a group that is formed by dividing a larger group by one of its normal subgroups. It is a mathematical concept used to simplify complex groups into smaller, more manageable ones.

How is a subgroup of a quotient group formed?

To form a subgroup of a quotient group, we first take a larger group and divide it by one of its normal subgroups. Then, we look for a subgroup within this quotient group that still satisfies all of the group's properties. This subgroup will be a subgroup of the original group as well.

Why is the statement "Subgroup of a Quotient is a Quotient of a Subgroup" important in group theory?

This statement is important because it allows us to simplify complex groups by breaking them down into smaller, more manageable subgroups. It also helps us better understand the relationship between subgroups and quotient groups, and how they can be used to study the properties of larger groups.

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