[GAP Forum] a suggestion on the design of GAP

[Wilf Wilson]

Dear Benjamin,

I understand your annoyance at the similarly named commands with slightly different arguments and different capabilities.

I’d just like to note, for those who did not know, that the function AllIrreducibleSolvableGroups is contained in the PrimGrp package, whereas the command AllIrreducibleSolubleMatrixGroups (and the others, which are declared as synonyms) is contained in the Irredsol package. The documentation for each of these functions can be seen at https://gap-packages.github.io/primgrp/doc/chap2.html#X7DAC64F17C8B49A2 <https://gap-packages.github.io/primgrp/doc/chap2.html#X7DAC64F17C8B49A2> and https://www.gap-system.org/Manuals/pkg/irredsol/html/CHAP002.htm#SECT003 <https://www.gap-system.org/Manuals/pkg/irredsol/html/CHAP002.htm#SECT003> respectively.

Note also that the PrimGrp package is required by GAP, whereas Irredsol is not.

Best wishes,
Wilf

> On 18 Aug 2020, at 06:34, Benjamin Sambale <benjamin.sambale at gmail.com> wrote:
> 
> Dear GAP people,
> 
> let me start with a little puzzle: Which of the following commands behaves differently?
> 
> AllIrredSolMatrixGroups
> AllIrreducibleSolubleMatrixGroups
> AllIrreducibleSolvableGroups
> AllIrreducibleSolvableMatrixGroups
> 
> For a long time I have been thinking that they all were synonyms. Until recently, I observed that AllIrreducibleSolvableGroups is different. It takes slightly different arguments (Characteristic instead of Field) and has a limited range. For instance:
> 
> AllIrreducibleSolvableGroups(Dimension,8,Characteristic,2);
> #W  AllIrreducibleSolvableGroups: n = 8 outside range of library
> Error, all Dimension arguments outside range of library
> 
> AllIrreducibleSolvableMatrixGroups(Dimension,8,Field,GF(2)); #works
> 
> Now every time I want to list matrix groups I have to rethink what the "correct" command was. I can't think of a situation where AllIrreducibleSolvableGroups is superior to the other commands.
> So my suggestion is to remove this function. It would also help me memorizing to have just a single command instead of many synonyms (this also improves tab-completion on the command line).
> 
> Best wishes,
> Benjamin
> 
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