Problem with IS and EQUAL in evaluating equality of expressions



zeroequiv is not great, I agree.  We should definitely improve it.

However, it is not so much that it "tries harder" than is/equal.  It uses a
different, approximate technique which is supposed to be fast and reliable
for a very very narrow class of expressions (see the doc): differentiable,
single-variable, defined (no f(x)'s), etc.

On 5/13/06, Barton Willis <willisb at unk.edu> wrote:
>
> The function 'zeroequiv' claims to try a bit harder
> than does 'is(equal( ...))'....
> The required second argument is a puzzler--how can
> an expression vanish with respect to one variable, but
> not another? That's bogus.  We really should do better.