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

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

Lots of things should raise errors that don't currently:
~~~
assume(true>false)$ is(true>false) => unknown$
sign(a=b) => pnz
asksign({})
~~~

These are not real numbers in the mathematical sense (members of **R**) -- in fact, they are not numbers at all: ``ind, und, inf, minf, zeroa, zerob``, but they are real in the sense of not having a non-zero imaginary part (as opposed to ``infinity``), which is probably what is needed by most uses.



---

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

**Status:** maybe-fixed
**Group:** None
**Labels:** declare rectform featurep csign 
**Created:** Mon Jun 01, 2026 07:19 AM UTC by David Scherfgen
**Last Updated:** Tue Jun 02, 2026 09:30 AM 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.