Finite dimensional vector space V over the rationals which is not a subset of the reals and which is not a...












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This was a bonus question on an old assignment, unfortunately, I cannot find the solutions. The question asks to find an example of a finite dimensional vector space V over the rationals, where V is NOT a subset of the reals, and V is NOT a field.
I'm not too sure how one would approach this problem, any help would be appreciated










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    Polynomials with degree $leq n$ and rational coefficients should work I think.
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    – Joe
    Jan 23 at 15:54
















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$begingroup$


This was a bonus question on an old assignment, unfortunately, I cannot find the solutions. The question asks to find an example of a finite dimensional vector space V over the rationals, where V is NOT a subset of the reals, and V is NOT a field.
I'm not too sure how one would approach this problem, any help would be appreciated










share|cite|improve this question









$endgroup$








  • 1




    $begingroup$
    Polynomials with degree $leq n$ and rational coefficients should work I think.
    $endgroup$
    – Joe
    Jan 23 at 15:54














0












0








0





$begingroup$


This was a bonus question on an old assignment, unfortunately, I cannot find the solutions. The question asks to find an example of a finite dimensional vector space V over the rationals, where V is NOT a subset of the reals, and V is NOT a field.
I'm not too sure how one would approach this problem, any help would be appreciated










share|cite|improve this question









$endgroup$




This was a bonus question on an old assignment, unfortunately, I cannot find the solutions. The question asks to find an example of a finite dimensional vector space V over the rationals, where V is NOT a subset of the reals, and V is NOT a field.
I'm not too sure how one would approach this problem, any help would be appreciated







linear-algebra vector-spaces field-theory






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asked Jan 23 at 15:49









mmmmommmmo

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  • 1




    $begingroup$
    Polynomials with degree $leq n$ and rational coefficients should work I think.
    $endgroup$
    – Joe
    Jan 23 at 15:54














  • 1




    $begingroup$
    Polynomials with degree $leq n$ and rational coefficients should work I think.
    $endgroup$
    – Joe
    Jan 23 at 15:54








1




1




$begingroup$
Polynomials with degree $leq n$ and rational coefficients should work I think.
$endgroup$
– Joe
Jan 23 at 15:54




$begingroup$
Polynomials with degree $leq n$ and rational coefficients should work I think.
$endgroup$
– Joe
Jan 23 at 15:54










1 Answer
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What about $mathbb{Q}^2$? It satisfies all of those conditions.






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  • $begingroup$
    If I were to define multiplication like in the case of $R^2$, would it not give a subfield of the complex numbers?
    $endgroup$
    – mmmmo
    Jan 23 at 16:53






  • 1




    $begingroup$
    No. The set $mathbb{Q}^2$ is not a subset of $mathbb R$.
    $endgroup$
    – José Carlos Santos
    Jan 23 at 17:41











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1 Answer
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active

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1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









4












$begingroup$

What about $mathbb{Q}^2$? It satisfies all of those conditions.






share|cite|improve this answer









$endgroup$













  • $begingroup$
    If I were to define multiplication like in the case of $R^2$, would it not give a subfield of the complex numbers?
    $endgroup$
    – mmmmo
    Jan 23 at 16:53






  • 1




    $begingroup$
    No. The set $mathbb{Q}^2$ is not a subset of $mathbb R$.
    $endgroup$
    – José Carlos Santos
    Jan 23 at 17:41
















4












$begingroup$

What about $mathbb{Q}^2$? It satisfies all of those conditions.






share|cite|improve this answer









$endgroup$













  • $begingroup$
    If I were to define multiplication like in the case of $R^2$, would it not give a subfield of the complex numbers?
    $endgroup$
    – mmmmo
    Jan 23 at 16:53






  • 1




    $begingroup$
    No. The set $mathbb{Q}^2$ is not a subset of $mathbb R$.
    $endgroup$
    – José Carlos Santos
    Jan 23 at 17:41














4












4








4





$begingroup$

What about $mathbb{Q}^2$? It satisfies all of those conditions.






share|cite|improve this answer









$endgroup$



What about $mathbb{Q}^2$? It satisfies all of those conditions.







share|cite|improve this answer












share|cite|improve this answer



share|cite|improve this answer










answered Jan 23 at 15:51









José Carlos SantosJosé Carlos Santos

165k22132235




165k22132235












  • $begingroup$
    If I were to define multiplication like in the case of $R^2$, would it not give a subfield of the complex numbers?
    $endgroup$
    – mmmmo
    Jan 23 at 16:53






  • 1




    $begingroup$
    No. The set $mathbb{Q}^2$ is not a subset of $mathbb R$.
    $endgroup$
    – José Carlos Santos
    Jan 23 at 17:41


















  • $begingroup$
    If I were to define multiplication like in the case of $R^2$, would it not give a subfield of the complex numbers?
    $endgroup$
    – mmmmo
    Jan 23 at 16:53






  • 1




    $begingroup$
    No. The set $mathbb{Q}^2$ is not a subset of $mathbb R$.
    $endgroup$
    – José Carlos Santos
    Jan 23 at 17:41
















$begingroup$
If I were to define multiplication like in the case of $R^2$, would it not give a subfield of the complex numbers?
$endgroup$
– mmmmo
Jan 23 at 16:53




$begingroup$
If I were to define multiplication like in the case of $R^2$, would it not give a subfield of the complex numbers?
$endgroup$
– mmmmo
Jan 23 at 16:53




1




1




$begingroup$
No. The set $mathbb{Q}^2$ is not a subset of $mathbb R$.
$endgroup$
– José Carlos Santos
Jan 23 at 17:41




$begingroup$
No. The set $mathbb{Q}^2$ is not a subset of $mathbb R$.
$endgroup$
– José Carlos Santos
Jan 23 at 17:41


















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