Proving a = a^-1 implies a^2 = e in group theory

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SUMMARY

In group theory, it is established that if an element 'a' in a group G satisfies the condition a = a^-1, then it follows that a^2 = e, where e is the identity element of G. The proof is straightforward: starting from the assumption a = a^-1, one can derive that a^2 = aa = a(a^-1) = e. This conclusion is universally accepted and confirms the correctness of the proof presented in the discussion.

PREREQUISITES
  • Understanding of group theory concepts, specifically identity elements and inverses.
  • Familiarity with the notation and properties of groups, such as G, a, and e.
  • Basic algebraic manipulation skills to follow proofs in abstract algebra.
  • Knowledge of the implications of an element being its own inverse.
NEXT STEPS
  • Study the properties of identity elements in group theory.
  • Explore the concept of inverses in various algebraic structures.
  • Learn about different types of groups, such as abelian and non-abelian groups.
  • Investigate other proofs related to group properties and their implications.
USEFUL FOR

Students of abstract algebra, mathematicians focusing on group theory, and educators teaching foundational concepts in algebra will benefit from this discussion.

mehrts
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Let G be a group. Let 'a' be an element of G. Let e be the identity of G Prove that if a = a^-1 then a^2= e.

Is the proof below correct ?
Suppose a = a^-1. Then

a^2 = aa = a(a^-1) = e.
 
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yeah, if a is it's own inverse then a^2 is e. your proof looks fine to me.
 
Thxs. He he he :!)
 

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