featurep(e, real)



On 5/15/06, Barton Willis <willisb at unk.edu> wrote:

> featurep(e, real) := freeof(%i, rectform(e)).

OK by me. But can we suppress some of the asksign nuttiness
that crops up in rectform ?

> declare(F, real_domain,  reals)
> declare(F, real_codomain, reals)
> declare(F, complex_domain, complex)
> declare(F, complex_codomain, complex)

Maxima is pretty good at syntax extensions. How about something
that reads more like the way ordinary math notation reads? e.g.

  declare (F, maps_into (foo, bar))
  declare (F, foo maps_into bar)
  declare (F, maps foo into bar)
  declare (F, [domain foo, codomain bar])

Otherwise for every foo we need foo_domain, and bar_codomain for every bar.

What is the third argument?

> (4) Maxima should signal domain errors ASAP.

Well, I'm not so sure about that.

> If I start to fill my car up with diesel fuel, I want a error message
> before the first drop. I don't an engine light  to come on in Ogallala,
> Nebraska (seconds before the fire).

Preferably at about 3 o'clock in the morning. That way you can
ponder the constellations while waiting for help ....

> So yes,  signum(%i)  should signal an error.  As for cos(a # b),
> well GIGO, I suppose.

I don't see anything inherently garbageful about cos (a # b).
As for signum (%i), let me think about that.

best,
Robert