#1351 is(if a>0 and a>0 and a>0 ...) => internal error

[Stavros Macrakis]

is(if a>0 and a>0 then 1) => unknown (OK)

is(if a>0 and a>0 and a>0 then 1)
=>
Maxima encountered a Lisp error:
Error in PROGN [or a callee]: Bad plist
((MGREATERP $A (0 DATA (((MGRP ...

Same for

is(if a>0 and a>0 and a>0 then true else false)

i.e. it is not because the return value is a non-boolean

Maxima 5.13.0 http://maxima.sourceforge.net
Using Lisp GNU Common Lisp (GCL) GCL 2.6.8 (aka GCL)

[Dieter Kaiser]

This bug may be related to the bug SF[1891911] "is(f(a+b+c)) --> Lisp error".

Here we have an even or odd number of arguments to AND. The algorithm fails at the same point in the routine QUEUE+P in db.lisp as for the bug SF[1891911].

Dieter Kaiser

[Dieter Kaiser]

The error of this bug report is no longer present in Maxima 5.20post. We get:

(%i1) is(if a>0 and a>0 and a>0 then 1);
(%o1) unknown

(%i2) is(if a>0 and a>0 and a>0 then true else false);
(%o2) unknown

Closing this bug report as "works for me".
Dieter Kaiser