Definition: Let
be a subset of
and let
be a sequence of functions defined on
We say that
converges pointwise on
if
exists for each point![]()
This means that
is a real number that depends only on![]()
If
is pointwise convergent then the function defined by![]()
for every
is called the pointwise limit of the sequence![]()
More formally, given any
and
there exists a natural number
depending only on
and
such that
for every![]()
Definition Let
be a subset of
and let
be a sequence of real valued functions defined on
Then
converges uniformly to
if given any
there exists a natural number
such that
for every![]()
depends only on
so uniform convergence implies pointwise convergence., but the converse is not true.
Example:![]()
As
for each
so
converges pointwise to zero.
Suppose now that
and
then
and
so
is not uniformly convergent.