Is R^2 a Field with Component Wise Operations?

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Discussion Overview

The discussion centers on whether R^2 can be considered a field when using component-wise operations for addition and multiplication. It explores the implications of this classification in the context of field theory and integral domains.

Discussion Character

  • Debate/contested

Main Points Raised

  • One participant initially questions if R^2 is a field under component-wise operations, suggesting that it might be valid.
  • A later edit from the same participant retracts the initial question, indicating a reconsideration of the argument.
  • Another participant raises a specific query about the inverse of the element (3,0), which highlights a potential issue with defining inverses in this context.
  • Another contribution states that the direct product of two non-trivial integral domains, such as R and S, cannot be an integral domain due to the presence of zero-divisors, implying that R^2 cannot be a field.

Areas of Agreement / Disagreement

Participants do not reach a consensus, as there are competing views regarding the classification of R^2 as a field and the implications of zero-divisors in the context of integral domains.

Contextual Notes

Participants express uncertainty about the definitions and properties of fields and integral domains, particularly regarding the existence of inverses and the implications of zero-divisors.

quasar987
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Hello,

Am I missing something or is R^2 a field with the obvious component wise addition and multiplication (a,b)*(c,d)=(ac,bd)?
 
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EDIT: Completely ignore this. Didn't think it through. For an example of why it's false see Office Shredder's reply.

Yes if R is a field, then R^2 is a field (clearly commutative, and (a,b) has inverse (1/a,1/b) ).
 
Last edited:
What's the inverse of (3,0)?
 
Ok, that's what I was missing :)
 
If R, S are non-trivial integral domains, then their direct product [itex]R\times S[/itex] is never an integral domain, because it always has zero-divisors: (a,0).(0,b)=0. In particular, this holds for fields.
 

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