[Maxima-bugs] [maxima:bugs] Re: #4749 Declaring a symbol both real and complex or real and imaginary

[Stavros M. <mac...@us...>]

Maxima is not very consistent about all this. For example, we have the ``domain=real/complex`` variable which sounds very powerful, but in fact the only thing it affects is the simplification of ``(a^b)^c`` as far as I can tell.

One pragmatic definition of ``kind(z,complex)`` is that ``imagpart(z)`` returns the nounform ``'imagpart(z)`` and not 0. 

Grepping through the code, it looks as though there are three ways that the declaration is used:  ``kindp, decl-complexp, featurep``. These are used for ``real/complex/imaginary`` in the files ``compar (sign-any), conjugate (manifestly-XXX-p), rpart, simp``.  But I haven't looked at the transitive closure of function calls....



---

**[bugs:#4749] Declaring a symbol both real and complex or real and imaginary**

**Status:** open
**Group:** None
**Labels:** declare rectform featurep csign 
**Created:** Mon Jun 01, 2026 07:19 AM UTC by David Scherfgen
**Last Updated:** Mon Jun 01, 2026 09:19 PM UTC
**Owner:** nobody


Maxima allows declaring a symbol both `real` and `complex` and even both `real` and `imaginary`. I think that in the second case, it should at least issue a warning, if not an error.

For the first case, where a symbol is declared both `real` and `complex`, Maxima behaves differently across `csign`, `rectform` and `featurep`:

~~~
(%i1) declare(x, real, x, complex);
(%o1) done

(%i2) csign(x);
(%o2) complex

(%i3) rectform(x);
(%o3) x

(%i4) featurep(x, real);
(%o4) true

(%i5) featurep(x, complex);
(%o5) true
~~~

These functions all have a different concept ...


---

Sent from sourceforge.net because max...@li... is subscribed to https://sourceforge.net/p/maxima/bugs/

To unsubscribe from further messages, a project admin can change settings at https://sourceforge.net/p/maxima/admin/bugs/options.  Or, if this is a mailing list, you can unsubscribe from the mailing list.