On 27 January 2014 14:37, <kroe...@uni-math.gwdg.de> wrote: > Ok, I will do the upstream-report (Singular trac at > http://www.singular.uni-kl.de:8002/trac/newticket) > >> John Cremona: [...] which I'm sure has been reported before. > > > I could not find a corresponding ticket in sage trac and cannot > currently login. Could someone open a that ticket in sage-trac if necessary?
I will do that (unless Peter has already). Despite Singular, Sage can check for the unit ideal in this and related functions. John > > > Jack > > Am Montag, 27. Januar 2014 15:15:08 UTC+1 schrieb Peter Bruin: >> >> Hello, >> >> > I'm a bit confused about Sage's answer if Ideal(1) is prime. >> > >> > R.<x,y>= QQ[] >> > I = Ideal(R(1)) >> > I.is_prime() >> > >> > Sage (5.11, not only) says yes, >> > conflicting to the definition, >> > http://en.wikipedia.org/wiki/Prime_ideal >> > Has somebody an expanation of this behaviour? >> >> The example Singular session below suggests that the problem lies in >> Singular (I'm not too familiar with Singular, but I think the answers >> should all be the same, and only primdecSY(J) seems to be correct). >> >> Peter >> >> >> $ sage -singular >> SINGULAR / >> Development >> A Computer Algebra System for Polynomial Computations / version >> 3-1-5 >> 0< >> by: W. Decker, G.-M. Greuel, G. Pfister, H. Schoenemann \ Jul 2012 >> FB Mathematik der Universitaet, D-67653 Kaiserslautern \ >> > LIB "primdec.lib" >> (...) >> > ring R = 0, (x, y), dp; >> > ideal I = 1; >> > primdecSY(I); >> [1]: >> [1]: >> _[1]=1 >> [2]: >> _[1]=1 >> > primdecGTZ(I); >> [1]: >> [1]: >> _[1]=1 >> [2]: >> _[1]=1 >> > ideal J = x, x + 1; >> > primdecSY(J); >> empty list >> > primdecGTZ(J); >> [1]: >> [1]: >> _[1]=1 >> [2]: >> _[1]=1 >> > -- > You received this message because you are subscribed to the Google Groups > "sage-support" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sage-support+unsubscr...@googlegroups.com. > To post to this group, send email to sage-support@googlegroups.com. > Visit this group at http://groups.google.com/group/sage-support. > For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To post to this group, send email to sage-support@googlegroups.com. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/groups/opt_out.
