Let $R$ be an integral domain and $P$ be a prime ideal in $R[x]$ such that $Pcap R={0}$. Show that...











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Let $R$ be an integral domain and $P$ be a prime ideal in $R[x]$ such that $P cap R={0}$. Show that $:operatorname{height}Ple 1$. please help to find its height...










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Let $R$ be an integral domain and $P$ be a prime ideal in $R[x]$ such that $P cap R={0}$. Show that $:operatorname{height}Ple 1$. please help to find its height...










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put on hold as off-topic by user26857, user302797, jgon, Chinnapparaj R, Cesareo yesterday


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – user26857, user302797, jgon, Chinnapparaj R, Cesareo

If this question can be reworded to fit the rules in the help center, please edit the question.













  • Please use MathJax math.meta.stackexchange.com/questions/5020/…
    – Anurag A
    Nov 13 at 18:56










  • Welcome to Maths SX! Do you know rings of fractions?
    – Bernard
    Nov 13 at 19:03













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Let $R$ be an integral domain and $P$ be a prime ideal in $R[x]$ such that $P cap R={0}$. Show that $:operatorname{height}Ple 1$. please help to find its height...










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Let $R$ be an integral domain and $P$ be a prime ideal in $R[x]$ such that $P cap R={0}$. Show that $:operatorname{height}Ple 1$. please help to find its height...







commutative-algebra






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edited 2 days ago









user26857

39.1k123882




39.1k123882










asked Nov 13 at 18:50









Ravi Agarwal

121




121




put on hold as off-topic by user26857, user302797, jgon, Chinnapparaj R, Cesareo yesterday


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – user26857, user302797, jgon, Chinnapparaj R, Cesareo

If this question can be reworded to fit the rules in the help center, please edit the question.




put on hold as off-topic by user26857, user302797, jgon, Chinnapparaj R, Cesareo yesterday


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – user26857, user302797, jgon, Chinnapparaj R, Cesareo

If this question can be reworded to fit the rules in the help center, please edit the question.












  • Please use MathJax math.meta.stackexchange.com/questions/5020/…
    – Anurag A
    Nov 13 at 18:56










  • Welcome to Maths SX! Do you know rings of fractions?
    – Bernard
    Nov 13 at 19:03


















  • Please use MathJax math.meta.stackexchange.com/questions/5020/…
    – Anurag A
    Nov 13 at 18:56










  • Welcome to Maths SX! Do you know rings of fractions?
    – Bernard
    Nov 13 at 19:03
















Please use MathJax math.meta.stackexchange.com/questions/5020/…
– Anurag A
Nov 13 at 18:56




Please use MathJax math.meta.stackexchange.com/questions/5020/…
– Anurag A
Nov 13 at 18:56












Welcome to Maths SX! Do you know rings of fractions?
– Bernard
Nov 13 at 19:03




Welcome to Maths SX! Do you know rings of fractions?
– Bernard
Nov 13 at 19:03










1 Answer
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Note that the statement holds if $R$ is a field. Now consider the localization of $R[x]$ at $R$, which is a polynomial ring over the field $K(R)$, where $K(R)$ is the field of fractions of $R$. Since $Pcap R={0}$, $P$ is still a prime ideal. It is easy to show that any kind proper inclusion $Qsubset P$ of prime ideals will hold in $K(R)[x]$. Hence the height of $P$ in $R[x]$ and in $K(R)[x]$ are the same. The latter one is at most one and the result follows.






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    1 Answer
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    1 Answer
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    Note that the statement holds if $R$ is a field. Now consider the localization of $R[x]$ at $R$, which is a polynomial ring over the field $K(R)$, where $K(R)$ is the field of fractions of $R$. Since $Pcap R={0}$, $P$ is still a prime ideal. It is easy to show that any kind proper inclusion $Qsubset P$ of prime ideals will hold in $K(R)[x]$. Hence the height of $P$ in $R[x]$ and in $K(R)[x]$ are the same. The latter one is at most one and the result follows.






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      up vote
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      Note that the statement holds if $R$ is a field. Now consider the localization of $R[x]$ at $R$, which is a polynomial ring over the field $K(R)$, where $K(R)$ is the field of fractions of $R$. Since $Pcap R={0}$, $P$ is still a prime ideal. It is easy to show that any kind proper inclusion $Qsubset P$ of prime ideals will hold in $K(R)[x]$. Hence the height of $P$ in $R[x]$ and in $K(R)[x]$ are the same. The latter one is at most one and the result follows.






      share|cite|improve this answer























        up vote
        3
        down vote










        up vote
        3
        down vote









        Note that the statement holds if $R$ is a field. Now consider the localization of $R[x]$ at $R$, which is a polynomial ring over the field $K(R)$, where $K(R)$ is the field of fractions of $R$. Since $Pcap R={0}$, $P$ is still a prime ideal. It is easy to show that any kind proper inclusion $Qsubset P$ of prime ideals will hold in $K(R)[x]$. Hence the height of $P$ in $R[x]$ and in $K(R)[x]$ are the same. The latter one is at most one and the result follows.






        share|cite|improve this answer












        Note that the statement holds if $R$ is a field. Now consider the localization of $R[x]$ at $R$, which is a polynomial ring over the field $K(R)$, where $K(R)$ is the field of fractions of $R$. Since $Pcap R={0}$, $P$ is still a prime ideal. It is easy to show that any kind proper inclusion $Qsubset P$ of prime ideals will hold in $K(R)[x]$. Hence the height of $P$ in $R[x]$ and in $K(R)[x]$ are the same. The latter one is at most one and the result follows.







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        answered Nov 13 at 19:08









        Levent

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        3,386825















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