"Michael Burschik" <xxxxxx@lotto-berlin.de> writes:

> > > But my point that an empty vector is a pathological case
> > remains valid.
> > > An empty list, or an empty collection/set, however, is
> > perfectly legitimate.
> >
> > There is nothing more pathological about an empty vector than any of
> > the others.
>
> I seem to recall that zero-dimensional vectors were considered something of
> an oddity in my algebra classes, and I am pretty certain that I have never
> used one, whereas I use empty lists and empty sets on a regular basis, but
> maybe you are right.

They are like the empty set: they seem odd only until they seem second
nature, at which point they are ordinary and boring.  Rather like
zero, actually.

What is slightly odder is a matrix of dimension zero; such a matrix
necessarily has no elements.  This is unusual, because for any other
dimension, a single-element matrix is possible.  That means that you
can convert scalars to matrixes for any dimension but zero.

Still, not a big deal.