Ralf Hemmecke <[email protected]> writes:

>>>> It would be nicer to have a domain specifically for finite series, I
>>>> think.  But no time...
>>>
>>> But this is one of the most fundamental domains: List. And it's
>>> already done. ;-)
>>
>> Not series: sequences!  Thus: it's SparseUnivariatePolynomial, but lazy.
>
> You want what. Lists, that evaluate lazily like stream, but are
> always supposed to be finite. So you want to be able to call expand
> on a lazy list like [n for n in 0..10^(10^10))]?

why are you exaggerating?

> What do you gain?

equality for reasonable cases.  But, to be honest, I do not know why

++ Author: Clifton J. Williamson

decided to use UPXS instead of SUP as representation.  The only reason I
can think of is lazyness.

ExponentialOfUnivariatePuiseuxSeries(FE,var,cen):_
      Exports == Implementation where
  FE  : Join(Field, Comparable)
  var : Symbol
  cen : FE
  UPXS ==> UnivariatePuiseuxSeries(FE,var,cen)

  Exports ==> Join(UnivariatePuiseuxSeriesCategory(FE),OrderedAbelianMonoid) _
        with
    exponential : UPXS -> %
      ++ exponential(f(x)) returns \spad{exp(f(x))}.
      ++ Note: the function does NOT check that \spad{f(x)} has no
      ++ non-negative terms.
    exponent : % -> UPXS
      ++ exponent(exp(f(x))) returns \spad{f(x)}
    exponentialOrder: % -> Fraction Integer
      ++ exponentialOrder(exp(c * x ^(-n) + ...)) returns \spad{-n}.
      ++ exponentialOrder(0) returns \spad{0}.

  Implementation ==> UPXS add

    Rep := UPXS

    exponential f == complete f
    exponent f == f pretend UPXS
    exponentialOrder f == order(exponent f,0)

    zero? f == empty? entries complete terms f

    f = g ==
    -- we redefine equality because we know that we are dealing with
    -- a FINITE series, so there is no danger in computing all terms
      (entries complete terms f) = (entries complete terms g)


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