Kip Murray wrote"
>    allsubsets a       NB. order is wrong: "numeric" order of masks in verb
> ++-+-+--+
> ||b|a|ab|
> ++-+-+--+
>    Set allsubsets a   NB. correct order: "alpha" order from /:~
> ++-+--+-+
> ||a|ab|b|
> ++-+--+-+
>    pwrset a           NB. pwrset is allsubsets with /:~ inserted, see 
> below
>

I doubt if 'ordering' the elements of a set should be important.  An 
'ordered' set is a quite special class of set.  I am not sure what order ;: 
'apples oranges pears' should be in.

My functions were written to avoid the need for ordering.  It is however 
convenient to have a 'formal' or 'lexicographic' ordering for representing a 
set for some purposes.  The function Set provided that but is not required 
anywhere else.

For example the ordering of allsubsets given with Set is not a common 
ordering statisticians looking at the set of models of four factors would 
use.


Fraser 


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