I'm not seeing an instance where IndexSet is useful. For finite
collections of sets, it is redundant, as Union and Intersection can
already take a finite number of arguments. For infinite collections,
whatever symbol you index over would already exist in the collection
itself (for instance, n in Interval(2*n, 2*n + 1))

And you still haven't answered where infinite unions are needed for solveset.

Aaron Meurer

On Fri, Mar 23, 2018 at 12:14 AM, Yathartha Joshi <[email protected]> wrote:
> What I understood about BigUnion and BigIntersection from here. BigUnion for
> set of finitesets will work similar to union but for set of imagesets
> (infinite sets) we will be returning a unified solution.
>
> say for eg: [2*n , 2*n - 1 for n in Integers] passing it to Bigunion will
> yield something like [n for n in Integers] and BigIntersection would yield
> EmptySet.
>
> See https://github.com/sympy/sympy/issues/9815#issuecomment-373978030
>
> In solveset when union of imagesets are returned we can apply big union to
> get the unified result (probably could help the _union of imagesets once its
> implemented).
>
> IndexSet will be implemented to get access to set of sets through indexing,
> a number of sets will be passed as parameters and an instance of IndexSet
> will be returned with indices mapped to each of the sets in the sets. This
> way we can get access to a set of sets.
>
>>>> X = IndexSet(FiniteSet(1, 2, ,3), FiniteSet(4, 5)); X
>>>> X[0]
> FiniteSet(1, 2 ,3)
>>>>X[1]
> FiniteSet(4, 5)
>
>
> On Friday, March 23, 2018 at 5:44:13 AM UTC+5:30, Aaron Meurer wrote:
>>
>> Regarding BigUnion, what is the point of having it and IndexSet that
>> can only represent a finite number of sets? Union can already do this
>> without the indirection. I'm also unclear where this will be needed
>> for solveset.
>>
>> Aaron Meurer
>>
>> On Thu, Mar 22, 2018 at 4:38 PM, Yathartha Joshi <[email protected]>
>> wrote:
>> > Sorry I just gave the access to amit kumar, I have changed it, please
>> > have a
>> > look.
>> >
>> > Thanks!
>> >
>> >
>> > On Friday, March 23, 2018 at 1:54:31 AM UTC+5:30, Aaron Meurer wrote:
>> >>
>> >> When I click on that link it says I don't have access.
>> >>
>> >> I recommend starting your proposal on
>> >> https://summerofcode.withgoogle.com and linking the draft proposal
>> >> there. That will make it easier to find in the future.
>> >>
>> >> Aaron Meurer
>> >>
>> >> On Thu, Mar 22, 2018 at 4:01 PM, Yathartha Joshi <[email protected]>
>> >> wrote:
>> >> > I have created a proposal here. It would be great if you could review
>> >> > it
>> >> > and
>> >> > suggest any changes.
>> >> >
>> >> > Thanks in advance.
>> >> > Yathartha
>> >> >
>> >> > On Thursday, March 22, 2018 at 11:08:27 PM UTC+5:30, Yathartha Joshi
>> >> > wrote:
>> >> >>
>> >> >>
>> >> >> On Thursday, March 22, 2018 at 2:26:18 PM UTC+5:30, Amit Kumar
>> >> >> wrote:
>> >> >>>
>> >> >>> Hey Yathartha,
>> >> >>>
>> >> >>> That sounds good.
>> >> >>>
>> >> >>> Cheers!
>> >> >>> Amit
>> >> >>
>> >> >>
>> >> >> Okay! Thanks.
>> >> >>
>> >> >> Also, I was thinking was making absolute value expressions to work
>> >> >> in
>> >> >> complex domain. I found a few equations that have complex solutions:
>> >> >>
>> >> >>
>> >> >> http://www.wolframalpha.com/input/?i=solve(abs(x-2)+%2Babs(x)+-+7,+x)
>> >> >> http://www.wolframalpha.com/input/?i=solve(abs(x-2)+-2+,+x)
>> >> >>
>> >> >>
>> >> >>
>> >> >> http://www.wolframalpha.com/input/?i=solve(abs(x-2)+%2Babs(x+%2B4)+-+16,+x)
>> >> >>
>> >> >> I was trying to figure out a possible way to solve this, but I am
>> >> >> facing
>> >> >> difficulty in getting to the solution. I tried asking the question
>> >> >> here, and
>> >> >> got the only possible way. Can you provide me with some suggestions
>> >> >> regarding this? Is there a specific reason as to why solveset (and
>> >> >> even
>> >> >> solve) is not made to solve in complex domain.
>> >> >>
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