A question about the integral extension of a integral domain.











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Suppose that $R$ is an integral domain, $S$ is integral over $R$, that is to say, any elements in $S$ satisfies a monic polynomial with coefficients in $R$. (Here $S$ is a commutative ring with identity.) Is it right that $S$ is also an integral domain, or there is any counterexamples?










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    Take $S=R[x]/(x^2)$.
    – Mohan
    Nov 27 at 3:30















up vote
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Suppose that $R$ is an integral domain, $S$ is integral over $R$, that is to say, any elements in $S$ satisfies a monic polynomial with coefficients in $R$. (Here $S$ is a commutative ring with identity.) Is it right that $S$ is also an integral domain, or there is any counterexamples?










share|cite|improve this question


















  • 1




    Take $S=R[x]/(x^2)$.
    – Mohan
    Nov 27 at 3:30













up vote
-1
down vote

favorite









up vote
-1
down vote

favorite











Suppose that $R$ is an integral domain, $S$ is integral over $R$, that is to say, any elements in $S$ satisfies a monic polynomial with coefficients in $R$. (Here $S$ is a commutative ring with identity.) Is it right that $S$ is also an integral domain, or there is any counterexamples?










share|cite|improve this question













Suppose that $R$ is an integral domain, $S$ is integral over $R$, that is to say, any elements in $S$ satisfies a monic polynomial with coefficients in $R$. (Here $S$ is a commutative ring with identity.) Is it right that $S$ is also an integral domain, or there is any counterexamples?







commutative-algebra integral-domain integral-extensions






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asked Nov 27 at 3:12









Hugo

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  • 1




    Take $S=R[x]/(x^2)$.
    – Mohan
    Nov 27 at 3:30














  • 1




    Take $S=R[x]/(x^2)$.
    – Mohan
    Nov 27 at 3:30








1




1




Take $S=R[x]/(x^2)$.
– Mohan
Nov 27 at 3:30




Take $S=R[x]/(x^2)$.
– Mohan
Nov 27 at 3:30















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