Post new topic Reply to topic  [ 3 posts ] 
Author Message
 Post subject: question-multiplicative subsets
PostPosted: Thu Oct 23, 2008 11:37 am 

Joined: Thu Oct 23, 2008 11:16 am
Posts: 2
Hello everybody,

I would like to know if given a zero dimensional ideal J in Q[x1,...,xn] and a multiplicative subset S of Q[x1,...,xn] , it is possible to define in SINGULAR S-1(Q[x1,...,xn]/J).

And given g in Q[x1,...,xn] , is it possible to define in SINGULAR the saturation of J with respect to g?

thanks in advance for your help,
best wishes,
gema m.


Report this post
Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Sat Nov 15, 2008 2:57 am 

Joined: Mon Aug 29, 2005 9:22 am
Posts: 41
Location: Kaiserslautern, Germany
Hi,
You can localize in the maximal ideal <x1,...,xn> just by defining a local ring (local ordering, ends with an s = referring to series) eg.
ring r = 0,x(1..n),ds;
Localization in any other maximal ideal <x1-p1,...,xn-pn> is possible by translation of p to 0 (apply the translation to your ideal) and then as above.
Localizations w.r.t. arbitrary mlutiplicative sets are not possible.

If you wish to analyse a 0-dim ideal you should try a primary decomposition first.

sat(J,g); does the saturation.

Here is an example:

ring r = 0,(x,y,z),dp;
poly g = x3+y5+z2 +xyz;
ideal J = jacob(g);
LIB"primdec.lib";
primdecGTZ(J);
/*
[1]:
[1]:
_[1]=z2
_[2]=y3z
_[3]=30y4+y2z
_[4]=-y2z+6xz
_[5]=xy+2z
_[6]=3x2+yz
[2]:
_[1]=z
_[2]=y
_[3]=x
[2]:
[1]:
_[1]=z+3888000
_[2]=y-360
_[3]=x-21600
[2]:
_[1]=z+3888000
_[2]=y-360
_[3]=x-21600
*/
sat(J,g);
/*
[1]:
_[1]=z+3888000
_[2]=y-360
_[3]=x-21600
[2]:
1
*/


Report this post
Top
 Profile  
Reply with quote  
 Post subject: thanks -multiplicative subsets
PostPosted: Sat Nov 15, 2008 11:22 am 

Joined: Thu Oct 23, 2008 11:16 am
Posts: 2
thanks a lot for your answer,

kind regards,
gema m.


Report this post
Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 3 posts ] 

You can post new topics in this forum
You can reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

It is currently Fri May 13, 2022 11:05 am
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group