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Bug #1205

SyzOfGens: bug with zero generators

Added by Anna Maria Bigatti over 5 years ago. Updated over 5 years ago.

Status:
Closed
Priority:
Urgent
Assignee:
Anna Maria Bigatti
Category:
Improving
Target version:
CoCoALib-0.99600
Start date:
01 Aug 2018
Due date:
% Done:

100%

Estimated time:
5.01 h
Spent time:
5.00 h

Description

/**/  use R ::= QQ[x,y,z];
/**/  I := ideal([x, y, x+y, 0]);
/**/ SyzOfGens(I);

gives error.

(translate cocoa5 fix into cocoalib)

Related issues

Related to CoCoALib - Feature #1206: syz, SyzOfGens: which shifts for zero?Closed2018-08-02

Related to CoCoA-5 - Bug #1781: GenReprCompute: SERIOUS ERRORFeedback2024-02-08

Related to CoCoALib - Design #1647: Suppress zero from ideal generators? Detect 1 and simplify generators?Closed2022-01-20

History

#1 Updated by Anna Maria Bigatti over 5 years ago

  • Related to Feature #1206: syz, SyzOfGens: which shifts for zero? added

#2 Updated by Anna Maria Bigatti over 5 years ago

  • Status changed from In Progress to Feedback
  • % Done changed from 10 to 90
/**/  use R ::= QQ[x,y,z];
/**/  I := ideal([x, y, x+y, 0]);
/**/  SyzOfGens(I);

but syzygies are automatically shifted with the degrees of the generators, and what's the degree of 0?
To avoid having to guess, we force the user to create the free module.
/**/  use R ::= QQ[x,y,z];
/**/  I := ideal([x, y, x+y, 0]);
/**/  R4 := NewFreeModule(R,4);
/**/  SyzOfGens(R4,I);

See #1206 for follow-ups.

#3 Updated by Anna Maria Bigatti over 5 years ago

  • Estimated time changed from 3.01 h to 5.01 h

#4 Updated by John Abbott over 5 years ago

  • Status changed from Feedback to Closed
  • % Done changed from 90 to 100

#5 Updated by Anna Maria Bigatti 3 months ago

  • Related to Bug #1781: GenReprCompute: SERIOUS ERROR added

#6 Updated by Anna Maria Bigatti 3 months ago

  • Related to Design #1647: Suppress zero from ideal generators? Detect 1 and simplify generators? added

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