Subgroup of a Quotient is a Quotient of a Subgroup

  • Thread starter Thread starter Szichedelic
  • Start date Start date
  • Tags Tags
    quotient Subgroup
Click For Summary
SUMMARY

The discussion centers on proving that a subgroup of a quotient group G/N is also a quotient of a subgroup of G. The fourth isomorphism theorem is pivotal in this proof, establishing that if H is a subgroup of G/N, then H is isomorphic to a subgroup of G formed as H/N. The ambiguity in the teacher's statement regarding whether "quotient of a subgroup of G" refers to another normal subgroup or a subgroup of G is noted, but the conclusion remains that the proof aligns with the fourth isomorphism theorem, provided the theorem is permissible for citation in the homework context.

PREREQUISITES
  • Understanding of group theory concepts, specifically quotient groups.
  • Familiarity with normal subgroups and their properties.
  • Knowledge of the fourth isomorphism theorem.
  • Basic proof techniques in abstract algebra.
NEXT STEPS
  • Study the fourth isomorphism theorem in detail.
  • Explore examples of quotient groups and their subgroups.
  • Review the properties of normal subgroups in group theory.
  • Practice proving statements related to subgroup and quotient group relationships.
USEFUL FOR

This discussion is beneficial for students studying abstract algebra, particularly those focusing on group theory, as well as educators seeking to clarify concepts related to quotient groups and isomorphisms.

Szichedelic
Messages
28
Reaction score
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.
 
Physics news on Phys.org
I think your approach is fine.
 
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.
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 11 ·
Replies
11
Views
4K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K