Theorem
Ifis the quotient of a metric space
defined by
where
is the equivalence relation on the set of Cauchy sequences in
defined by:
if
with
Thenis a completion of
Proof
Lebe a Cauchy sequence in
is dense in
Proof here.
Hence for allthere exists
such that
Henceis also a Cauchy sequence, converging to
Proof here.
Thenconverges to
The conclusion is thatis complete.