Cc: Michael Stillman <mike@math.cornell.edu>
From: David Eisenbud <de@msri.org>
To: dan@math.uiuc.edu
In-Reply-To: <200803031929.m23JTqoE012197@u123.math.uiuc.edu>
Subject: Re: Request
Date: Mon, 3 Mar 2008 22:27:13 -0800

I think "topComponents" probably works
now only in Gorenstein rings. But it wouldn't be hard to make it work
in general. Let's do this when we meet...

David


--
David Eisenbud
Professor of Mathematics,
University of California, Berkeley
www.msri.org/~de


On Mar 3, 2008, at 11:29 AM, Daniel R. Grayson wrote:

>
> Yes, we should probably add that, provided it also works in quotient  
> rings,
> which I assume it does.  David, does it?
>
>> Cc: "Ms. Mousumi Mandal" <mousumi@math.iitb.ac.in>,
>>        David Eisenbud <de@msri.org>
>> From: Michael Stillman <mike@math.cornell.edu>
>> To: Dan Grayson <dan@math.uiuc.edu>
>> Subject: Re: Request
>> Date: Sun, 2 Mar 2008 19:09:54 -0500
>>
>> Should we add such a function to M2?
>>
>> symbolicPower(ZZ,Ideal) := (n,J) -> topComponents(J^n)
>>
>> or at least mention it in the documentation somewhere?
>>
>> -- Mike
>>
>> On Mar 2, 2008, at 3:49 PM, David Eisenbud wrote:
>>
>>> Dear Ms Mandal,
>>>
>>> The script is by now built into M2 (get the newest
>>> version, 1.1).
>>>
>>> If I is an ideal in a polynomial ring, the
>>> topComponents(I)
>>> returns the intersection of the primary components of
>>> highest dimension of I. Therefore, if P is prime,
>>>
>>> topComponents(P^n)
>>>
>>> is the n-th symbolic power.
>>>
>>> David Eisenbud
