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Bug #355

Colon of zero ideal fails (zero-divisors)

Added by John Abbott almost 11 years ago. Updated over 10 years ago.

Status:
Closed
Priority:
Urgent
Category:
Maths Bugs
Target version:
Start date:
24 May 2013
Due date:
% Done:

100%

Estimated time:
Spent time:

Description

The following excerpt exhibits the problem.

/**/ Use R ::= QQ[x,y,z];
/**/ I:=ideal(x);
/**/ RmodI:= R/I;
/**/ Use RmodI;
/**/ Ideal(zero(RmodI)):Ideal(x);

***************************************************************************
****CoCoA ERROR****  ErrCode: CoCoA::ERR::ZeroRingElem
****CoCoA ERROR****  Message: Non-zero RingElem required
****CoCoA ERROR****  Context: LPP(f)
****CoCoA ERROR****  File:    ../../include/CoCoA/SparsePolyRing.H
****CoCoA ERROR****  Line:    395
***************************************************************************

NB: Laura needs a way to test whether a ringelem is a zero-divisor for the COCOA School.


Related issues

Related to CoCoALib - Feature #356: IsZeroDivisorClosed2013-05-24

History

#1 Updated by Anna Maria Bigatti almost 11 years ago

  • Assignee set to Anna Maria Bigatti
  • Target version set to CoCoALib-0.9953
  • % Done changed from 0 to 60

fixed.
Meanwhile compute

/**/ Use R;
/**/ I:=ideal(x*y);
/**/ RmodI:= R/I;
/**/ Use RmodI;
/**/ I:Ideal(CanonicalRepr(x));
ideal(y) -- in R
--- or
/**/ Ideal(RmodI,[]):Ideal(x);
ideal((y)) -- in R/I

#2 Updated by Anna Maria Bigatti almost 11 years ago

  • Status changed from New to Feedback
  • % Done changed from 60 to 90

#3 Updated by Anna Maria Bigatti over 10 years ago

all fixed (it didn't like to have a 0 in the divisor's generators).
Meanwhile IsZeroDivisor has been implemented and is working fine.

#4 Updated by Anna Maria Bigatti over 10 years ago

  • Status changed from Feedback to Closed
  • Target version changed from CoCoALib-0.9953 to CoCoALib-0.99531
  • % Done changed from 90 to 100

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