Hi Oleksandr!
Am 08.09.2009 um 15:25 schrieb Oleksandr:
>
> Hi,
>
> On Sep 7, 3:17 pm, Michael Brickenstein <brickenst...@mfo.de> wrote:
>> Am 07.09.2009 um 14:34 schrieb Oleksandr:
>>> What about Sage implementation for
>>
>>> 1. weighting vector(s) "a(w1, w2...wn)",
>>> 2. free module orderings (e.g. c/C) mixed somewhere in between? Does
>>> Sage have such a concept?
>>
>> I suppose, that the answer is no.
>>> In Sage i'd imagine something like:
>>> {{{
>>> TermOrder = WeightVector(2,5) + ModuleOrder('c') + WeightVector
>>> (-1,-2)
>>> + MatrixOrder(1,1,0,-1)
>>> }}}
>> I suppose, the best thing is to separate that into a ModuleOrder,
>> which builds on a TermOrder.
>
> I am not sure what do you mean by that?
> Note that one can mixin a ModuleOrder somewhere in between TermOrder-
> s.
I am referring to the fact, that it is sensible
to assume, that for each component the ordering on the component is
the same as on the polynomial
ring.
SchreyerOrdering(exponents=[(list of integers)], term_order=TermOrder
(..))
ComponentFirst(term_order=..., ascending=True)# (c, dp)
ComponentLast(...)
I agree with you, that Schreyer orderings should be exposed to the
surface.
Using that assumption, the problem of a module ordering becomes
orthogonal to the Term Ordering.
Cheers,
Michael
>
> Well, I guess one needs a concept comprising all the possible
> alternatives (even of) module orderings...
> It would be nice to have a Syzygy and Schreyer (free module) orderings
> as well!
>
> As of Singular - please remember that ANY ordering is a module
> ordering:
> e.g. simply using something like "(dp)" actually means "(dp, C)"!
>
> Oleksandr
>
--~--~---------~--~----~------------~-------~--~----~
To post to this group, send an email to sage-devel@googlegroups.com
To unsubscribe from this group, send an email to
sage-devel-unsubscr...@googlegroups.com
For more options, visit this group at http://groups.google.com/group/sage-devel
URLs: http://www.sagemath.org
-~----------~----~----~----~------~----~------~--~---
