Project

General

Profile

Feature #978

CommonDenom: for polys and lists?

Added by John Abbott over 7 years ago. Updated over 5 years ago.

Status:
Closed
Priority:
Normal
Assignee:
Category:
CoCoA-5 function: new
Target version:
Start date:
21 Nov 2016
Due date:
% Done:

100%

Estimated time:
1.01 h
Spent time:

Description

Should there be a function called CommonDenom (or something similar)?

For polynomials? For lists of polynomials?


Related issues

Related to CoCoA-5 - Support #977: "universal denominator" (related with GroebnerFanIdeals)In Progress2016-11-17

History

#1 Updated by John Abbott over 7 years ago

In fact there is already an undocumented builtin fn called CommonDenom, but only for RINGELEM. The fn also exists in CoCoALib (and is documented there).

What are the exact semantics? And what should they be?

Should the fn be extended to lists of RINGELEM? (also in CoCoALib?)

#2 Updated by John Abbott over 7 years ago

  • Related to Support #977: "universal denominator" (related with GroebnerFanIdeals) added

#3 Updated by John Abbott over 7 years ago

Some aspects to consider when deciding the semantics:
  • we may assume that the result is positive (if coeffs in QQ)
  • defn is clear in QQ[x,y,z]
  • should it also work for QQ[a,b][x,y,z]?
  • should it also work for QQ(a,b)[x,y,z] or FrF(ZZ[a,b])[x,y,z]
  • should it work for an element of QQ or even of ZZ?

If we make it work for lists of RINGELEM, should it be recursive (e.g. so it would work for list of list of RINGELEM)?

#4 Updated by Anna Maria Bigatti almost 7 years ago

  • Target version changed from CoCoA-5.2.0 spring 2017 to CoCoA-5.2.2
  • We are going to work on this, better postpone this.

#5 Updated by Anna Maria Bigatti over 6 years ago

  • Target version changed from CoCoA-5.2.2 to CoCoA-5.2.4

Work on "ideals mod p" still in progress.
Postpone to next version.

#6 Updated by John Abbott almost 6 years ago

  • Status changed from New to Resolved
  • % Done changed from 0 to 80

This appears already to have been done (and documented).
Feedback? Close?

#7 Updated by Anna Maria Bigatti over 5 years ago

  • Status changed from Resolved to Closed
  • Assignee set to John Abbott
  • % Done changed from 80 to 100
  • Estimated time set to 1.01 h

Also available in: Atom PDF