#1 Resultant fails on simple algebraic extensions

[luisfe]

Version: 3-0-1
System: Mac Os X 10.3.9
Installed via fink unstable.

The resultant function fails when it is used on a
simple algebraic extension.

>ring r=(0,a),(x,y),dp;
>resultant(x^2-1,x+1,x);
0

>ring r=(0,a),(x,y),dp;
>minpoly=a^3+2*a+2;
>resultant(x^2-1,x+1,x);
1

Expected result:
0

If using the resultant when the ring is a simple
algebraic extension, it always return 1 unless one of
the polynomials equals 0.

If it is the expected behaviour (ie. it is not
implemented) then, it should be documented. I have
found nothing about that on the documentation.