#3292 fourier_elim((x>=-1 and x<=1) and x=0, [x]) gives emptyset

[Michael.Soegtrop]

This is tested with Maxima 5.38.1, SBCL 64, Windows.

The following result is incorrect:

(%i2) fourier_elim((x>=-1 and x<=1) and x=0, [x]);
(%o2) emptyset

Reformulating this without and gives the correct result:

(%i5) fourier_elim([x>=-1, x<=1, x=0], [x]);
(%o5) [x=0]

Best regards,

Michael

[David Scherfgen]

fourier_elim expects a list of single inequations, so I think this is correct behavior, i.e. not a bug. But maybe the function should print a warning if it sees that the input is not of the expected format.

[Michael.Soegtrop]

Dear David,

this was disussed on the list. Barton Willis asked me to report it (I should have mentioned this above):

https://sourceforge.net/p/maxima/mailman/message/35712699/

Also see describe(fourier_elim) - towards the end.

Best regards,

Michael

[Barton Willis]

In a fresh Maxima, I get

(%i1)   ((x>=-1 and x<=1) and x=0);
(%o1)   false

Thus fourier_elim receives false as its first argument. After that, it returns emptyset. No this isn't a problem with the fourier_elim code.