Is the Product of A and An in a Cyclic Group of Order n Outside the Group?

In summary, a cyclic group of order n has all its elements in the form A, A2, A3, ..., An, where A is an arbitrary element. According to the definition of a group, the product of two elements A and B must be an element C of the group. However, within a cyclic group, the product of A and An will result in An+1, not one of the elements of the group. Instead, An+1 is equal to the identity element of the group. Therefore, An = 1 and An+1 = A.
  • #1
yicong2011
75
0
Given a cyclic group of order n, with all its elements in the form :

A, A2, A3, ..., An

where A is an arbitrary element of the group.



According to the definition of group,

"The product of two arbitrary elements A and B of the group must be an element C of the group",

That is to say,

AB = C = an element of G


I just wonder that within a cyclic group, the product of element A and An should be An+1, yet An+1 is not one of the element of a cyclic group of order n.
(since, all elements within a cyclic group of order n should has the form :

A, A2, A3, ..., An

where A is an arbitrary element of the group.

)
 
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  • #2
In a finite cyclic group of order n and generated by the element [itex] A [/itex]
[itex] A^{n+1} = [/itex] the identity element of the group
 
  • #3
Stephen Tashi said:
In a finite cyclic group of order n and generated by the element [itex] A [/itex]
[itex] A^{n+1} = [/itex] the identity element of the group

Don't you mean An = 1? So then An+1 = A.
 
  • #4
spamiam said:
Don't you mean An = 1? So then An+1 = A.

You're right.
 
  • #5


This is indeed a valid observation. The product of two elements in a cyclic group should result in another element within that group. In this case, A and An are both elements of the group, but their product An+1 is not. This can be seen as a limitation of the definition of a cyclic group of order n, as it does not include all possible products of elements within the group. However, this does not necessarily mean that the group is not cyclic or that there is a problem with the definition. It simply means that some products may not be included in the set of elements of the group. This could be further explored and studied in the context of the specific group and its properties.
 

FAQ: Is the Product of A and An in a Cyclic Group of Order n Outside the Group?

What is a cyclic group?

A cyclic group is a mathematical structure that consists of a set of elements and a binary operation that combines any two elements to produce a third element in the set. The group is called cyclic because there exists an element, called the generator, that can be repeatedly combined with itself to produce the entire set.

What is a problem in cyclic group?

A problem in cyclic group refers to a mathematical problem that involves finding a specific element, such as the generator or a particular power of the generator, in a given cyclic group. These problems are often used in cryptography and coding theory.

Can cyclic groups have infinite order?

Yes, cyclic groups can have infinite order. This means that the generator can be combined with itself an infinite number of times to produce new elements in the group. However, there are also cyclic groups with finite order, meaning that the generator can only be combined a finite number of times to produce all the elements in the group.

What is the order of a cyclic group?

The order of a cyclic group is the number of elements in the group. It is equal to the number of times the generator needs to be combined with itself to produce all the elements in the group. For example, a cyclic group with order 5 would have the elements {1, 2, 3, 4, 5} and the generator would need to be combined with itself 5 times to produce all of these elements.

What is the significance of cyclic groups in mathematics?

Cyclic groups have many applications in different branches of mathematics, such as group theory, abstract algebra, and number theory. They are also used in cryptography, coding theory, and other areas of computer science. In addition, cyclic groups have connections to other mathematical structures, such as rings and fields, making them a fundamental concept in mathematics.

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