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

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SUMMARY

The discussion centers on proving that a group G is abelian if it satisfies the condition (a*b)^2 = (a^2)*(b^2) for all elements a, b in G. The key steps involve expanding the left-hand side to (ab)(ab) = abab and recognizing that the right-hand side simplifies to aabb. By equating these expressions, it becomes clear that for G to hold this equality, the elements must commute, thus confirming that G is abelian.

PREREQUISITES
  • Understanding of group theory concepts, specifically group operations.
  • Familiarity with the properties of abelian groups.
  • Knowledge of binomial expansion in algebra.
  • Basic skills in mathematical proof techniques.
NEXT STEPS
  • Study the properties of abelian groups in group theory.
  • Learn about other conditions that imply a group is abelian.
  • Explore examples of non-abelian groups to contrast with abelian groups.
  • Investigate the implications of the identity (a*b)^n = (a^n)*(b^n) for various n.
USEFUL FOR

Students of abstract algebra, mathematicians focusing on group theory, and anyone interested in the foundational properties of algebraic structures.

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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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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.
 

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