Singular
https://www.singular.uni-kl.de/forum/

qring of an nc_algebra
https://www.singular.uni-kl.de/forum/viewtopic.php?f=10&t=2710		 Page 1 of 1
Author:  michaelk [ Mon Jan 22, 2018 9:13 pm ]
Post subject:  qring of an nc_algebra
I am running the following code in the "Try Online" section of the website (running version 4.1.0) from Nov. 2016:

Code:
LIB "nctools.lib";
ring A = 0,(a,b),dp;
def S = nc_algebra(-1,0);
setring S;
b^2==0;
ideal I = a^2;
qring R = twostd(I);
setring R;
b^2==0;


The first call of b^2==0 (after setring S) returns 0 (false), whereas the second call of b^2==0 (after setring R) yields 1 (true). I don't understand why this is the case, since b^2 is not be in the ideal generated by a^2. Am I doing something wrong?
Author:  hannes [ Thu Feb 01, 2018 11:55 am ]
Post subject:  Re: qring of an nc_algebra
No, nothing wrong: you found a bug in Singular.
The test for being a SCA ring had a bug.
It is now fixed in the sources with
https://github.com/Singular/Sources/commit/4fd796a9c41904bd840bcc8a2691b4dac9865de4
Page 1 of 1 All times are UTC + 1 hour [ DST ]
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
http://www.phpbb.com/