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Feature #1150

New fn: transform ideal with ring hom

Added by John Abbott about 6 years ago. Updated almost 4 years ago.

Status:
New
Priority:
Normal
Assignee:
-
Category:
New Function
Target version:
CoCoALib-1.0
Start date:
22 Jan 2018
Due date:
% Done:

0%

Estimated time:
Spent time:
0.20 h

Description

Do we want a new fun for transforming an ideal with a ringhom?
TransformIdeal(const ideal& I, const RingHom& phi)

[taken from a photo of the whiteboard]

History

#1 Updated by John Abbott almost 4 years ago

  • Description updated (diff)

What is this supposed to mean? Does it mean the ideal generated by {phi(f) | f in I}? What else could it mean?
When might it be useful?

Short example: let $P = QQ[x]$ and let phi send x |-> x^2, so phi is not surjective.
Let $I$ be the ideal generated by $x$. Then ${phi(f) | f in I}@ is not an ideal.

Let G be any set of generators of I. Then given the proposed definition in line 1 of this note,
we have that phi(G) is a set of generators of phi(I).

Given this defn, impl should be easy... but is it useful for anyone?

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