Opened 10 years ago
Closed 2 years ago
#12803 closed defect (fixed)
quotient of ideals throws up Singular bug
Reported by:  mariah  Owned by:  malb 

Priority:  minor  Milestone:  sage9.1 
Component:  commutative algebra  Keywords:  
Cc:  malb  Merged in:  
Authors:  Markus Wageringel  Reviewers:  Kwankyu Lee 
Report Upstream:  Fixed upstream, in a later stable release.  Work issues:  
Branch:  873857a (Commits, GitHub, GitLab)  Commit:  873857a0005b3a2cb0979bf4b04918dab9bf8d30 
Dependencies:  Stopgaps:  #17679 
Description (last modified by )
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+xe2*xv); I = Ideal(3, 3*xv1, 3); I2 = Ideal(3, 3*xv1); assert( I == I2 ) Q1 = J.quotient(I) # wrong Q2 = J.quotient(I2) assert( Q1 == Q2 ) # fails
Change History (14)
comment:1 Changed 10 years ago by
 Cc malb added
 Component changed from algebra to commutative algebra
 Owner changed from AlexGhitza to malb
comment:2 Changed 9 years ago by
 Milestone changed from sage5.11 to sage5.12
comment:3 Changed 8 years ago by
 Milestone changed from sage6.1 to sage6.2
comment:4 Changed 8 years ago by
comment:5 Changed 8 years ago by
 Milestone changed from sage6.2 to sage6.3
comment:6 Changed 8 years ago by
 Milestone changed from sage6.3 to sage6.4
comment:7 Changed 8 years ago by
 Report Upstream changed from N/A to Fixed upstream, in a later stable release.
comment:8 Changed 7 years ago by
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+xe2*xv); I = Ideal(3, 3*xv1, 3); I2 = Ideal(3, 3*xv1); assert( I == I2 ) Q1 = J.quotient(I) # wrong Q2 = J.quotient(I2) assert( Q1 == Q2 ) # fails
comment:9 Changed 7 years ago by
 Description modified (diff)
comment:10 Changed 7 years ago by
 Stopgaps set to #17679
comment:11 Changed 7 years ago by
 Description modified (diff)
comment:12 Changed 2 years ago by
 Branch set to u/ghmwageringel/12803
 Commit set to 873857a0005b3a2cb0979bf4b04918dab9bf8d30
 Milestone changed from sage6.4 to sage9.1
 Priority changed from major to minor
 Status changed from new to needs_review
Since the bug is fixed, here is a branch removing the stopgap warning and adding the example from the description as a doctest.
(Ignore the pyflakes warning for now. I will deal with it on another ticket, as the unused macaulay2 variable should actually be used.)
New commits:
873857a  12803: remove stopgap and add doctest

comment:13 Changed 2 years ago by
 Reviewers set to Kwankyu Lee
 Status changed from needs_review to positive_review
LGTM
comment:14 Changed 2 years ago by
 Branch changed from u/ghmwageringel/12803 to 873857a0005b3a2cb0979bf4b04918dab9bf8d30
 Resolution set to fixed
 Status changed from positive_review to closed
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This bug (and some others) are fixed in recent Singular:
(offtopic: are all known Singularbugs reported upstream? )
However, I recall that there are some issues when considering updating Singular :