Non-Abelian Group: (ab)^2 = (b^2)(a^2)?

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In summary, the question being discussed is whether in a non abelian group, the expression (ab)^2 is equal to (b^2)(a^2). The conversation includes an example of expanding this expression in the smallest non abelian group, S_3, and the concept of inversion in a group. The final answer is that (ab)^2 does not necessarily equal (b^2)(a^2) in a non abelian group.
  • #1
math-chick_41
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in a non abelian group does (ab)^2 = (b^2)(a^2)?
this isn't homework, my semester is over.
 
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  • #2
1. Just expand (ab)^2

2. Or look in the smallest non abelian group there is: S_3
 
  • #3
it expands to abab , but how come (ab)^-1 = (b^-1)(a^-1)?
 
  • #4
because inversion reverses the order of the elements, it is an anti-automorphism and has nothing to do with the commutativity or otherwise of the group.

we know the inverse of ab is a c such that abc=1, bc=a^{-1}, and then c=b^{-1}a^{-1}
 
  • #5
ok, thanks.
 
  • #6
math-chick_41 said:
it expands to abab , but how come (ab)^-1 = (b^-1)(a^-1)?

What do you get if you multiply (ab)(b-1a-1)?
 

FAQ: Non-Abelian Group: (ab)^2 = (b^2)(a^2)?

What is a Non-Abelian Group?

A Non-Abelian Group is a mathematical structure that follows the group axioms, but does not satisfy the commutative property. This means that the order in which group elements are multiplied matters.

What does the equation (ab)^2 = (b^2)(a^2) mean?

The equation (ab)^2 = (b^2)(a^2) is a special property of Non-Abelian Groups called the inverse square property. It states that the product of two group elements, when squared, is equal to the square of each element multiplied in reverse order.

How is this property different from the commutative property?

The commutative property states that the order of multiplication does not matter, while the inverse square property of Non-Abelian Groups shows that the order of multiplication does matter.

Can this property be applied to all Non-Abelian Groups?

No, not all Non-Abelian Groups have the inverse square property. This property is specific to certain types of Non-Abelian Groups, such as dihedral groups and quaternion groups.

What are some real-world applications of Non-Abelian Groups with the inverse square property?

Non-Abelian Groups with the inverse square property have applications in various fields such as physics, chemistry, and cryptography. They can be used to describe the symmetries of physical systems and molecules, and to create secure encryption algorithms.

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