Application in permutations group

In summary, the question asks for the proof that the application fg: G→G is in Sg for each g ∈ G, given the group of automorphisms Aut(G) and permutations group Sg. The solution involves showing that the functions f_g are well-defined and have an obvious inverse, thus making them bijections and members of Sg. The additional condition states that f_g = id(G) only when g = e, and that the group operation is respected by the embedding of G into Sym(G).
  • #1
Dassinia
144
0
Hello
I am studying for my exam and there's a question that i don't know how to solve, I have some difficulties with symmetric/permutations groups

1. Homework Statement

Consider a finite group of order > 2.
We write Aut(G) for the group of automorphisms of G and Sg for the permutations group of the set G.
Consider a1 and a2 ∈ Aut(G) two automorphisms.
We suppose that the g=1 is the only element g ∈ G such as ∀ x ∈ G we have a1(g)*x=x*a2(g)
For g,x ∈ G we have
fg(x):=a1(g)*x*a2(g-1)
Show that for each g ∈ G the application fg: G→G is in Sg

Homework Equations

The Attempt at a Solution


I really don't know how to do that..
 
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  • #2
I don't get the problem here. Since all f_g are well-defined functions on the finite set G with an obvious inverse
h_g (x) := a1(g^-1)*x*a2(g) = f_g^-1 (x), i.e. a bijection, they have to be in Sg, if Sg is Sym(G) the set of all bijections on G.

The additional condition says that f_g = id(G) implies g = e. It is also true that f_g * f_h = f_ (g*h).
Therefore you have a group monomorphism f: G → Sym(G) with f(g) := f_g, i.e. an embedding of G into Sym(G) that respects the group operation.
 
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1. What is an application in permutations group?

An application in permutations group is a mathematical concept that involves rearranging a set of elements in a specific order. This rearrangement is known as a permutation, and the set of all possible permutations of a given set of elements make up the permutations group. Applications in permutations group can be used to solve problems in fields such as mathematics, computer science, and physics.

2. How is the concept of permutations group used in real-life applications?

The concept of permutations group has various real-life applications, including cryptography, data encryption, and data compression. It is also used in computer algorithms for sorting and searching data, as well as in statistical analysis and probability theory.

3. What are some common examples of permutations group?

Some common examples of permutations group include the Rubik's cube, which has over 43 quintillion possible permutations, and the game of chess, where the positions of the pieces on the board can be seen as permutations of the starting position. Other examples include DNA sequencing and shuffling a deck of cards.

4. How can the concept of permutations group be applied in problem-solving?

The concept of permutations group can be used to solve problems by systematically listing out all possible permutations and then analyzing them to determine if a solution exists. This can be especially helpful in combinatorial problems where the order of elements is important, such as in arranging a group of people in a specific order or creating unique passwords.

5. What are some key properties of permutations group?

Some key properties of permutations group include closure, associativity, identity element, and inverse element. Closure means that the result of combining two permutations will also be a permutation. Associativity means that the order in which permutations are combined does not affect the result. Identity element refers to the permutation that leaves all elements unchanged, and inverse element refers to the permutation that reverses the effects of another permutation.

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