complete metric space
<theory> A {metric space} in which every sequence that
converges in itself has a limit. For example, the space of
{real numbers} is complete by {Dedekind's axiom}, whereas the
space of {rational numbers} is not - e.g. the sequence a[0]=1;
a[n_+1]:=a[n]/2+1/a[n].
(1998-07-05)