Post new topic Reply to topic  [ 1 post ] 
Author Message
 Post subject: Old rinvar examples don't work anymore
PostPosted: Tue May 13, 2014 9:25 am 

Joined: Mon May 12, 2014 8:26 pm
Posts: 1
Hi all,

I'm trying to do some invariant theory computations with Singular, using the rinvar.lib by Thomas Bayer. I ran into some problems (I'm completely new to Singular), so I decided to try some example code that I found on his old website (link below). However, the following example from his invariant-theory examples script produces an error:
Code:
//////////////////////////////////////////////////////////////////
// infinite, reductive (sl2 on V+V+Sym^2V) (ub = 3)

ring S3 = 0,(s(1..4), t(1..7)), lp;
ideal G = s(1)*s(4) - s(2)*s(3) - 1;
ideal action = s(1)*t(1) + s(2)*t(2), s(3)*t(1) + s(4)*t(2), s(1)*t(3) + s(2)*t(4), s(3)*t(3) + s(4)*t(4),s(1)^2*t(5) + 2*s(1)*s(2)* t(6) + s(2)^2*t(7), s(1)*s(3)*t(5) + (s(1)*s(4) + s(2)*s(3))*t(6) + s(2)*s(4)*t(7), s(3)^2*t(5) + 2*s(3)*s(4)*t(6) + s(4)^2 * t(7);
//int time = timer; ideal inv = Invariants(G, action, 3); time = timer - time; time; //

Actually, that code doesn't produce an error, but when I replace the commented call to "Invariants" with a call to InvariantRing(std(G), action), as in the examples for the current rinvar.lib, I get the error:
Quote:
def R = InvariantRing(std(G), action);
? ideal not zerodimensional
? leaving zeroset.lib::zeroSet
? leaving rinvar.lib::ReynoldsOperator
? leaving rinvar.lib::InvariantRing


Maybe his Invariants function is not the same as the InvariantRing function that is currently in Singular? I tried running his old (2002) script (link below), but could not get it to work. Any ideas what the problem is and how to fix it?

Thanks!

I'm not allowed to post links, so take out the spaces in the following:
old website of Thomas Bayer: www14 . in . tum . de/personen/bayert/software.html#Invariants
Old version of rinvar.lib: wwwmayr . informatik . tu-muenchen . de/personen/bayert/invariants


Report this post
Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 1 post ] 

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 Dec 15, 2017 4:42 am
cron
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group