[GAP Forum] The stability of group libraries

[Alexander Konovalov]

Dear Leonard,

Thank you - that's really an important issue. My understanding is that the indexing
should stay the same for all the time, i.e. outputs of TransitiveGroup(m,n) should 
be isomorphic in any version of the library.

IMHO, other information may change - it looks fine to me if e.g. in a new version a 
group will be given by more optimal presentation. The mechanism to alert users stays 
with their authors, and they should be encouraged to list all potentially disruptive 
changes in release announcements and documentation.

Best wishes
Alexander







On 28 Jan 2015, at 13:38, Leonard Soicher <l.h.soicher at qmul.ac.uk> wrote:

> Dear GAP Developers, Dear GAP-Forum,
> 
> I would like to know what the policy is concerning the groups
> in the the very useful GAP libraries of transitive permutation groups and 
> of primitive permutation groups (and any other group library you wish to comment on) 
> as regards to any possible changes wihen changes are made in GAP. In particular, 
> were the actual groups in the library, their GeneratorsOfGroup, and their indexing 
> within the library fixed in perpetuity when the library was initially made available in GAP4,
> and if not, what is the mechanism to alert users to any changes? This is important
> for being able to repeat, check, report on, and extend results made using specific 
> groups in a given  library. 
> 
> Thank you for your help,
> Leonard
> 
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