Question about sets
Tue, 20 Aug 2002 14:19:53 -0500
"Scott J." <email@example.com> wrote:
> As far a I know sets can implemented by implementing a list of
> anything(a list of all types) The sets Haskell does have are AFAIK
> sets of elements of the same type: these are not general sets.
Ah. That's a static typing issue.
However, I don't think it's really an issue. In axiomatic set theory,
every set must be a subset of some other set, except for powersets and
unions. Unions are implementable using Either, and powersets are
implementable using Set (i.e., powerset :: Set a -> Set (Set a)).