Re: Handling branch cuts for hypergeometric functions

[Richard Fateman , Sat, 12 Feb 2005 08:17:40 -0800]:
> > Or is there a way to turn them off that I have missed so far?
> 
> I think that if you say  "assume(x>0)"  it will not ask "is x positive".
> (etc.)

But for that you have to know beforehand that Maxima will ask about
the sign of x.  This is no problem for simple manipulations where you
know what questions to expect, but not in general.

> I think it is a mistake to silently make assumptions that are "typical"
> because it is often the most important cases in which the assumptions
> fail. The boundary or singular conditions that are part of a solution
> are the ones that may exhibit engineering failure modes.

Obviously, but how does that relate to what I proposed?  Maybe it is
due to my poor command of the English language that is at fault.

Anyway, just to clarify: When the user states "use the following
values to answer any questions you may have", and Maxima returns a
structure that lists the conditions that Maxima actually used in the
evaluations, there are no silent assumptions nor is there any loss of
information.  Indeed, I get even more information as the conditions so
generated may be more general than an assumption I might choose: e.g.,
if I am only interested in the case a > 1, it might nevertheless be
interesting to learn that the result is valid for a > 0.

Albert.