Re: [sage-devel] Re: Modules(ZZ) vs CommutativeAdditiveGroups()

On 29 May 2014 09:40, Nicolas M. Thiery wrote: > Hi Simon, > > On Wed, May 28, 2014 at 03:36:09PM +, Simon King wrote: >> Are you sure that this is a problem? In order to construct ZZ, we need >> CommutativeAdditiveGroups()---which is already there. Now, someone does >> Modules(ZZ)---a

Re: [sage-devel] Re: Modules(ZZ) vs CommutativeAdditiveGroups()

Hi Simon, On Wed, May 28, 2014 at 03:36:09PM +, Simon King wrote: > Are you sure that this is a problem? In order to construct ZZ, we need > CommutativeAdditiveGroups()---which is already there. Now, someone does > Modules(ZZ)---and of course we can make it so that it returns > Commuta

[sage-devel] Re: Modules(ZZ) vs CommutativeAdditiveGroups()

Hi Nicolas, On 2014-05-28, Nicolas M. Thiery wrote: > So far, the two categories have not been merged for a stupid > bootstrapping reason: to construct Modules(ZZ), we need to construct > ZZ. To construct ZZ, an abelian group, we need to construct the > category CommutativeAdditiveGroups(). So if

[sage-devel] Re: Modules(ZZ) vs CommutativeAdditiveGroups()

Hi Nathann, On 2014-05-27, Nathann Cohen wrote: > I do not understand much about categories, but if we implement > multiplication by a positive integer for semigroups and multiplication by a > negative integer for semigroup with inverse, won't this automatically give > a ZZ-Module structure to

Re: [sage-devel] Re: Modules(ZZ) vs CommutativeAdditiveGroups()

> Mathematically that is exactly right, there is no difference between > "Z-module" and "abelian group" just as there is none between > (commutative) "Z-algebra" and "ring". We know this, but the point was > whether the two things could or should be distinguished in Sage. Well, if the ticket give

Re: [sage-devel] Re: Modules(ZZ) vs CommutativeAdditiveGroups()

On 28 May 2014 00:51, Nathann Cohen wrote: > Could this be related ? > > http://trac.sagemath.org/ticket/16384 > > I do not understand much about categories, but if we implement > multiplication by a positive integer for semigroups and multiplication by a > negative integer for semigroup with inve

[sage-devel] Re: Modules(ZZ) vs CommutativeAdditiveGroups()

Could this be related ? http://trac.sagemath.org/ticket/16384 I do not understand much about categories, but if we implement multiplication by a positive integer for semigroups and multiplication by a negative integer for semigroup with inverse, won't this automatically give a ZZ-Module struct

[sage-devel] Re: Modules(ZZ) vs CommutativeAdditiveGroups()

Hello, That's interesting, I asked myself exactly the same question in relation to . Something like this does work correctly for modules over a field: sage: Modules(QQ) Category of vector spaces over Rational Field I was wondering if it would be easy to