Can Different Bases Change the Classification of Lie Algebras?

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SUMMARY

The discussion centers on the implications of changing bases in Lie algebras, specifically the transition from su2 to sl2 and from the Cartan-Weyl basis of sl3 to a Chevalley basis. The original poster, Dan, questions the accuracy of referring to sl2 as su2 due to their differing structure factors. Additionally, the change from the Cartan basis to the Chevalley basis alters the properties of the root system, which raises concerns about the consistency of terminology in academic texts.

PREREQUISITES
  • Understanding of Lie algebras, specifically su2 and sl2.
  • Familiarity with the Cartan-Weyl basis and Chevalley basis of sl3.
  • Knowledge of structure factors in Lie algebra theory.
  • Basic concepts of root systems in the context of Lie algebras.
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  • Research the structural differences between su2 and sl2 in detail.
  • Study the properties and applications of the Cartan-Weyl basis and Chevalley basis in sl3.
  • Explore the implications of changing bases on root systems in Lie algebras.
  • Examine academic standards for terminology consistency in mathematical texts.
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Mathematicians, physicists, and students studying Lie algebras, particularly those interested in the structural nuances and terminology used in theoretical physics and algebraic contexts.

topsquark
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This is only a minor question.

I watched an on-line video recently on su2 and how it applies to Physics. Now, one of the first things the instructor did was to change the base to sl2. Fine and all, but she called sl2 "su2" for the whole video. Since the two Lie algebras have different structure factors how can she do this? Or was she just being a Physicist and sloppy about it?

Another example. My text is talking about the Cartan-Weyl basis of sl3, then changes the basis to a Chevalley basis. The problem here is not merely that the structure factors are different but now the simply laced root system for the Cartan basis is no longer simply laced in the Chevalley basis. And yet the text still refers to it as sl3.

What gives?

-Dan
 

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