#18639: New class NumberFieldZeroIdeal
-------------------------+-------------------------------------------------
Reporter: | Owner:
cremona | Status: needs_work
Type: | Milestone: sage-6.10
defect | Resolution:
Priority: minor | Merged in:
Component: | Reviewers:
number fields | Work issues:
Keywords: | Commit:
Authors: John | 7be38840da684f9110b4a295712a7eb212f94318
Cremona | Stopgaps:
Report Upstream: N/A |
Branch: |
u/cremona/18639 |
Dependencies: |
#18622 |
-------------------------+-------------------------------------------------
Changes (by jdemeyer):
* milestone: sage-6.8 => sage-6.10
Old description:
> There are several issues with the zero ideal in number fields:
> {{{
> sage: K.<a> = NumberField(x^2-10)
> sage: K.<a> = NumberField(x^2-10)
> sage: 0/K.ideal(a)
> ------------------------------------------------------------------------
> Unhandled SIGSEGV: A segmentation fault occurred in Sage.
> This probably occurred because a *compiled* component of Sage has a bug
> in it and is not properly wrapped with sig_on(), sig_off().
> Sage will now terminate.
> ------------------------------------------------------------------------
> }}}
>
> {{{
> sage: K.<a> = QuadraticField(-5)
> sage: K.ideal(0) * K.ideal(a+1,3)
> ...
> PariError: incorrect type in basistoalg (t_MAT)
> }}}
>
> (and probably more)
>
> I propose to do some redesign and add a new class `NumberFieldZeroIdeal`
> for just the zero ideal. Then most methods of the current
> `NumberFieldIdeal` should probably be moved to either or both of
> `NumberFieldZeroIdeal`/`NumberFieldFractionalIdeal`.
New description:
There are several issues with the zero ideal in number fields:
{{{
sage: K.<a> = NumberField(x^2-10)
sage: K.<a> = NumberField(x^2-10)
sage: 0/K.ideal(a)
------------------------------------------------------------------------
Unhandled SIGSEGV: A segmentation fault occurred in Sage.
This probably occurred because a *compiled* component of Sage has a bug
in it and is not properly wrapped with sig_on(), sig_off().
Sage will now terminate.
------------------------------------------------------------------------
}}}
{{{
sage: K.<a> = NumberField(x^2-15)
sage: three = K.ideal(3)
sage: zero = K(0)
sage: three.divides(zero)
------------------------------------------------------------------------
Unhandled SIGSEGV: A segmentation fault occurred in Sage.
This probably occurred because a *compiled* component of Sage has a bug
in it and is not properly wrapped with sig_on(), sig_off().
Sage will now terminate.
------------------------------------------------------------------------
}}}
{{{
sage: K.<a> = QuadraticField(-5)
sage: K.ideal(0) * K.ideal(a+1,3)
...
PariError: incorrect type in basistoalg (t_MAT)
}}}
(and probably more)
I propose to do some redesign and add a new class `NumberFieldZeroIdeal`
for just the zero ideal. Then most methods of the current
`NumberFieldIdeal` should probably be moved to either or both of
`NumberFieldZeroIdeal`/`NumberFieldFractionalIdeal`.
--
--
Ticket URL: <http://trac.sagemath.org/ticket/18639#comment:16>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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