limit of erfc



On Thu, May 17, 2012 at 1:02 PM, Stavros Macrakis <macrakis at alum.mit.edu>wrote:

> On Thu, May 17, 2012 at 3:50 PM, Raymond Toy <toy.raymond at gmail.com>wrote:
>>
>>
>> I take this to mean we shouldn't have atan(inf) -> %pi/2.  Which means
>> erf(inf) and friends should just return a noun.  But 0*inf always returns
>> 0. Shouldn't we return und for that?
>>
>
> We should either return und or leave it unsimplified.  Similarly for
> inf-inf, inf^0, is(equal(inf,inf)), etc. which currently return nonsense
> results.
>
> I believe someone shared code for this on the list, but it hasn't been
> integrated.  Not sure why.  Is it incomplete? Buggy?  Does it slow down
> simplification too much?
>

I had done some work on this long ago and I think Dieter has done some more
recent (better) work.  But, AFAIK, all attempts are incomplete.

Ray