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1d
comment A question about prime ideals
@Mathematician: I know enough about comaximal ideals to see that they have absolutely nothing to do with the question.
1d
comment In $K[X,Y]$, is the power of any prime also primary?
@Alex: you are right to doubt! See a non-primary square of a prime in Atiyah-Macdonald, page 51, Example 3).
2d
comment When does a principal divisor have degree 0?
There is no notion of degree for divisors (principal or not) on a proper scheme, unless you provide the scheme with some supplementary structure. What would the degree be ??
2d
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Sep
1
comment The ring $\mathbb{C}[x,y]/\langle xy \rangle$
Dear @rschwieb : your gracious comment does you credit. Everybody makes little mistakes but not everybody reacts the gentlemanly way you did.
Sep
1
comment The ring $\mathbb{C}[x,y]/\langle xy \rangle$
Great geometric answer: +1.
Sep
1
comment Equivalent conditions for an ideal to be zero-dimensional.
Yes, your comment is a perfect reason for your assertion and indeed the result is valid over any field (or even for any Jacobson ring, for users who know the concept). By the way, I had already upvoted your answer just before posting my comment.
Sep
1
comment Equivalent conditions for an ideal to be zero-dimensional.
"$\sqrt{I} = \mathfrak{m}_1 \cap \cdots \mathfrak{m}_r$ for some max ideals $\mathfrak{m}_i, \ldots$ of $R$" You should explain where that comes from.
Aug
31
comment Lines and projective isomorphism
$h_{21}$ needs to be nonzero (for example equal to $17$) , but not necessarily equal to $1$. Remember that $(0:1:0)=(0:17:0)$ . Also: your general matrix $\rho$ has certainly no reason to send $x_0=0$ to $x_0+x_1=0$. Why should it?
Aug
31
comment How do ideal quotients behave with respect to localization?
Perfect answer, Kevin: bravo!
Aug
31
revised Describe $Spec( \mathbb C[x,y]/x(x-a))$ where $a$ is some complex number.
added 424 characters in body
Aug
31
comment Describe $Spec( \mathbb C[x,y]/x(x-a))$ where $a$ is some complex number.
You are welcome, dear Arpit.
Aug
31
answered Describe $Spec( \mathbb C[x,y]/x(x-a))$ where $a$ is some complex number.
Aug
28
answered Is the quotient morphism from product of curves to to their symmetric product flat?
Aug
27
comment Riemann-Roch analysis of point divisor ring on smooth genus 3 Riemann surface
Dear @Tim, yes, I meant $l(3P)$ and I have corrected that typo. Many thanks for catching it.
Aug
27
revised Riemann-Roch analysis of point divisor ring on smooth genus 3 Riemann surface
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Aug
26
answered Riemann-Roch analysis of point divisor ring on smooth genus 3 Riemann surface
Aug
23
comment Non-orientable submanifolds
In general you can deduce nothing because Whitney's embedding theorem states that every manifold, orientable or not, can be embedded iinto some $\mathbb R^N$, which is of course orientable.
Aug
23
comment A problem regarding field theory
That you couldn't prove a false statement speaks in your favour: see my answer.
Aug
23
answered A problem regarding field theory