Solving Group Problems: |g| = 20 in G and Subgroup H = <x,y>

For c), <a>*<b> means the direct product of the two groups, so elements of the form (a^m, b^n) with m=0,1,2,3 and n=0,1,2,3,4,5. So you can just multiply elements to see what you get. In summary, we have computed |g^2| = 10 and |g^5| = 4 in group G with |g| = 20. We also know that |g^8| and |g^3| are equal to 1, since (g^8)^5 = (g^20)^2 = e and (g^3)^20 = (g
  • #1
hsong9
80
1

Homework Statement


A. Let |g| = 20 in a group G. Compute
|g^2|, |g^8|,|g^5|, |g^3|

B. In each case find the subgroup H = <x,y> of G.
a) G = <a> is cyclic, x = a^m, y = a^k, gcd(m,k)=d
b) G=S_3, x=(1 2), y=(2 3)
c) G = <a> * <b>, |a| = 4, |b| = 6, x = (a^2, b), y = (a,b^3)

The Attempt at a Solution


A. I know |g^2| = 20/2 = 10 and |g^5| = 20/5 = 4
But |g^8|, |g^3| don't know..

B. a)H=<a^d> , right?
but
I don't know how to solve b) and c)
Thanks!
 
Physics news on Phys.org
  • #2
hsong9 said:

The Attempt at a Solution


A. I know |g^2| = 20/2 = 10 and |g^5| = 20/5 = 4
But |g^8|, |g^3| don't know..

Don't forget that if [itex]g^{20}=e[/itex] then [itex]g^{40}=e[/itex] also.

B. a)H=<a^d> , right?

Yes.

but
I don't know how to solve b) and c)
Thanks!

b should be easy, because you've got a concrete group to play with. Just get in there and start computing. As for c, what does <a>*<b> mean?
 
  • #3
The least common multiple of 20 and 8 is 2*4*5= 40. [itex](g^8)^5= (g^20)^2= e[/itex].

The least common multiple of 3 and 20 is 60. [itex](g^3)^20= (g^20)^3= e[/itex].
 
  • #4
so.. for b) is H=(1 2) * (2 3) = (1 2 3)..?
 
  • #5
Yes, that's right.
 

1. What does |g| = 20 mean in this context?

|g| represents the order or number of elements in the group G. In this case, it means that there are 20 elements in the group G.

2. How is subgroup H defined?

Subgroup H is defined as the group generated by the elements x and y. This means that H contains all possible combinations of x and y, including their inverses, and the identity element.

3. How do you solve problems involving group G and subgroup H?

To solve problems involving group G and subgroup H, you need to first understand the properties and structure of both G and H. Then, you can use techniques such as Lagrange's Theorem or the Coset Enumeration Method to determine the number of elements and structure of H within G.

4. What is the significance of solving problems involving groups and subgroups?

Solving problems involving groups and subgroups has applications in various fields, such as mathematics, physics, and computer science. It allows us to understand and analyze complex structures and systems, as well as make predictions and solve real-world problems.

5. What are some common challenges when solving group problems?

Some common challenges when solving group problems include understanding the properties and structure of the group and subgroup, identifying the correct techniques to use, and determining the appropriate level of abstraction to approach the problem. It may also involve complex calculations and the need for a deep understanding of abstract algebra.

Similar threads

  • Calculus and Beyond Homework Help
Replies
2
Views
152
  • Calculus and Beyond Homework Help
Replies
8
Views
467
  • Calculus and Beyond Homework Help
Replies
6
Views
809
  • Calculus and Beyond Homework Help
Replies
1
Views
767
  • Calculus and Beyond Homework Help
Replies
5
Views
1K
  • Calculus and Beyond Homework Help
Replies
6
Views
557
  • Calculus and Beyond Homework Help
Replies
1
Views
1K
  • Calculus and Beyond Homework Help
Replies
7
Views
1K
  • Calculus and Beyond Homework Help
Replies
1
Views
2K
  • Calculus and Beyond Homework Help
Replies
3
Views
604
Back
Top