Theorem
Letand
be open balls in a metric space
and let
then a ball open in
exists such that
Proof
Letand
Suppose
so there exists
Sincethere exists an open ball
and since
there exists an open ball
Takethen
and
so
Theorem
Letand
be open balls in a metric space
and let
then a ball open in
exists such that
Proof
Letand
Suppose
so there exists
Sincethere exists an open ball
and since
there exists an open ball
Takethen
and
so