How can the ideal generated by ab-ba force a ring to commute?

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Discussion Overview

The discussion revolves around the concept of transforming a non-commutative ring into a commutative ring, exploring methods similar to those used in group theory, particularly through the use of ideals. The scope includes theoretical considerations and mathematical reasoning regarding ring structures and their properties.

Discussion Character

  • Exploratory
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • Some participants inquire whether it is possible to produce a commutative ring from a non-commutative one, drawing parallels to group theory.
  • One participant suggests that redefining multiplication to make all products zero could create a commutative ring, but acknowledges this may not be the least destructive method.
  • Another participant proposes factoring the ring by the two-sided ideal generated by the expression ab+ab, although this may have been a misunderstanding.
  • A clarification is made regarding the ideal, with a focus on the ideal generated by ab-ba as a potential method for forcing commutativity.
  • Discussion includes the consideration of matrix rings and the implications of eliminating elements of the form AB-BA, highlighting the destructiveness of such an operation.
  • Participants reflect on the differences between free groups and free abelian groups as an analogy to the discussion on rings.

Areas of Agreement / Disagreement

Participants express differing views on the methods to achieve commutativity in rings, with no consensus reached on a specific approach or solution. The discussion remains unresolved regarding the most effective or least destructive method.

Contextual Notes

Participants note potential misunderstandings regarding the ideal used for factoring, and there is an acknowledgment of the complexity involved in transforming ring structures without losing essential properties.

markiv
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Is there something you can do to a ring to produce a commutative ring? Like for any group, you can create an Abelian group by factoring out its commutator subgroup. Can you "force" a ring to commute?
 
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For a group, modding out by the commutator subgroup gives the largest abelian quotient. You could make a ring commutative by simply redefining multiplication such that cd=0 for every c,d in the ring, but I think what you're asking for is a "least destructive" way of making a ring commutative. I don't know the answer.
 
The simplest idea that comes to my mind: What about factoring the ring by the two-sided ideal generated by ab+ab?
 
I think you mean the ideal generated by ab-ba?
 
the most interesting rings are the matrix rings. you might think about how destructive it would be to kill all elements of form AB-BA.

also for a group you might reflect on the difference between the free group on two generators and the free abelian group ZxZ.
 
Landau said:
I think you mean the ideal generated by ab-ba?

Yes. My typo.
 

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