Opened 7 years ago

Last modified 4 years ago

#12803 new defect

quotient of ideals throws up Singular bug

Reported by: mariah Owned by: malb
Priority: major Milestone: sage-6.4
Component: commutative algebra Keywords:
Cc: malb Merged in:
Authors: Reviewers:
Report Upstream: Fixed upstream, in a later stable release. Work issues:
Branch: Commit:
Dependencies: Stopgaps: #17679

Description (last modified by jdemeyer)

This is a bug in Singular 3.1.7 (fixed in 4.0.1, see ticket #17254): 

R.<xe,xv> = ZZ[]

J = Ideal(4*xv^3+3*xv^2, 3*xe*xv^2+xe-2*xv);

I  = Ideal(-3, -3*xv-1, -3);
I2 = Ideal(-3, -3*xv-1);
assert( I  == I2 )

Q1 = J.quotient(I) # wrong
Q2 = J.quotient(I2)

assert( Q1 == Q2 ) # fails

Change History (11)

comment:1 Changed 7 years ago by SimonKing

  • Cc malb added
  • Component changed from algebra to commutative algebra
  • Owner changed from AlexGhitza to malb

comment:2 Changed 6 years ago by jdemeyer

  • Milestone changed from sage-5.11 to sage-5.12

comment:3 Changed 5 years ago by vbraun_spam

  • Milestone changed from sage-6.1 to sage-6.2

comment:4 Changed 5 years ago by jakobkroeker

This bug (and some others) are fixed in recent ​Singular: 

ring rng = integer,(x,y,z),dp;
ideal A = x^2, x*y, x*z;
ideal B = x;
quotient(A,B);
//_[1]=z
//_[2]=y
//_[3]=x

(offtopic: are all known Singular-bugs reported ​upstream? )

However, I recall that there are some issues when considering updating Singular :

  • there is no stable/official release yet
  • in sage-devel (?, cannot currently find the post I had in mind) it was mentioned that the libSingular interface changed significantly in comparison to v 3.1.6

comment:5 Changed 5 years ago by vbraun_spam

  • Milestone changed from sage-6.2 to sage-6.3

comment:6 Changed 5 years ago by vbraun_spam

  • Milestone changed from sage-6.3 to sage-6.4

comment:7 Changed 5 years ago by jakobkroeker

  • Report Upstream changed from N/A to Fixed upstream, in a later stable release.

comment:8 Changed 4 years ago by jakobkroeker

the bug above is fixed by upgrade to Singular 3.1.7

but there is at least another one (fixed in 4.0.1, see ticket #17254): 

R.<xe,xv> = ZZ[]

J = Ideal(4*xv^3+3*xv^2, 3*xe*xv^2+xe-2*xv);

I  = Ideal(-3, -3*xv-1, -3);
I2 = Ideal(-3, -3*xv-1);
assert( I  == I2 )

Q1 = J.quotient(I) # wrong
Q2 = J.quotient(I2)


assert( Q1 == Q2 ) # fails

comment:9 Changed 4 years ago by jakobkroeker

  • Description modified (diff)

comment:10 Changed 4 years ago by jakobkroeker

  • Stopgaps set to #17679

comment:11 Changed 4 years ago by jdemeyer

  • Description modified (diff)
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