Proving G is Abelian from (a*b)^2=(a^2)*(b^2)

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In summary, the equation (a*b)^2=(a^2)*(b^2) is a property known as the commutativity of multiplication, which is used to determine if a group is Abelian. An example of a group that satisfies this property is the group of real numbers under addition. However, there are other methods for proving a group is Abelian, such as showing that its operation is both associative and commutative. The commutativity of multiplication also plays an important role in the overall structure of a group, making it easier to understand and study. Additionally, this property can be used to prove other properties of a group, such as the existence of an identity element and inverses, as well as the distribut
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Homework Statement


If G is a group such that (a*b)^2=(a^2)*(b^2) for all a,b in G, show that G must be abelian.


The Attempt at a Solution


First, I tried to expand the binomial (a*b)^2 and set it equal to (a^2)*(b^2). But then I didn't know where to go from there.
 
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  • #2
You aren't trying very hard. A group is abelian if ab=ba for all a and b. (ab)^2=abab. (a^2)*(b^2)=aabb. Take it from there.
 

1. How can (a*b)^2=(a^2)*(b^2) be used to prove that G is Abelian?

The equation (a*b)^2=(a^2)*(b^2) is a property known as the commutativity of multiplication. This means that the order of elements in a group does not affect the outcome of the operation. If G satisfies this property, it is considered to be Abelian.

2. Can you provide an example of a group that satisfies (a*b)^2=(a^2)*(b^2) and is therefore Abelian?

Yes, the group of real numbers under addition is an example of a group that satisfies (a*b)^2=(a^2)*(b^2). This can be seen by choosing any two real numbers, x and y, and showing that (x+y)^2 = x^2 + y^2, which is the commutative property.

3. Is proving G is Abelian from (a*b)^2=(a^2)*(b^2) the only method for proving Abelian groups?

No, there are other properties and methods for proving that a group is Abelian. For example, if a group's operation is both associative and commutative, it is automatically Abelian.

4. How does proving G is Abelian from (a*b)^2=(a^2)*(b^2) relate to the overall structure of a group?

The commutativity of multiplication is an important property in the structure of a group, as it determines the order in which elements can be multiplied. If a group is Abelian, its structure is simpler and more predictable, making it easier to study and understand.

5. Can (a*b)^2=(a^2)*(b^2) be used to prove other properties of a group besides Abelianity?

Yes, this property can be used to prove other properties such as the existence of an identity element and inverses, as well as the distributivity of multiplication over addition in a ring. It is a fundamental property in the study of groups and their structures.

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