Is x^2/y^2 an Ideal in the Ring F[x, y]?

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Discussion Overview

The discussion revolves around the expression x²/y² in the context of the ring F[x, y] and whether it can be considered an ideal. Participants explore the implications of defining such an expression within polynomial rings and fields.

Discussion Character

  • Debate/contested

Main Points Raised

  • One participant questions whether x²/y² is an element of F[x, y], suggesting uncertainty about its status within the ring.
  • Another participant asserts that x²/y² is undefined in F[x, y] due to the inability to divide in that ring, and thus questions the validity of considering it as an ideal.
  • A participant reflects on the origin of the question, indicating a possible misunderstanding related to fraction fields and expressing confusion about the notation used.
  • It is noted that F(x, y) / (x² / y²) also lacks meaning, as the only ideals in a field are the zero ideal and the field itself, leading to a suggestion that the intended expression might have been F[x, y] / (x², y²).
  • A later reply acknowledges the clarification provided by other participants, indicating a resolution of confusion but not necessarily agreement on the initial question.

Areas of Agreement / Disagreement

Participants express disagreement regarding the status of x²/y² in F[x, y], with some asserting it is undefined and others questioning its implications. The discussion remains unresolved regarding whether x²/y² can be treated as an ideal.

Contextual Notes

Limitations include the misunderstanding of notation and the context of fraction fields versus polynomial rings, which may affect the interpretation of the expressions discussed.

matness
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let F be a field.x^2/y^2 is not an element of F[x,y](is it?)
(x^2/y^2) can or can not be ideal in F[x,y] ?
 
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Strictly speaking, the expression

x²/y²

is undefined, because one cannot divide in the ring F[x, y]. And because x²/y² is undefined, so is the expression (x²/y²).


We're usually more generous with notation, though; rather than leave x²/y² undefined, we implicitly shift our attention to the field F(x, y), which does contain an element by that name.

Where did this come from?
 
the origin of my question:i have to prove F[x,y]/(x^2/y^2) is a vector space it seemed a bit meaningless anddid not remember fraction fields
probably it was F(x,y)/(x^2/y^2) and i misread it
sorry:rolleyes:
 
F(x, y) / (x² / y²) doesn't make much sense either; the only ideals of a field are the zero ideal and the whole field itself.

It probably said F[x, y] / (x², y²)
 
now it is clear thank you very much
 

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