University Maths Notes: Complex Analysis – Analytic Continuation
We start with a
Definition Let
and
be
analytic functions whose domains are the regions
and
respectively.
and
are
direct analytic continuations of each other if there is a region
such
that
for![]()
Example:
is
only defined for
but
we may write
on
the region defined by
but
is
defined on the wider region![]()
is
an analytic continuation of![]()
Example:
is
normally defined on the region
so
that![]()
We in fact only need Log to be one to one on the complex plane so
that the inverse is defined. We can instead define Log_1 z on
so that
for
and
we have extended
to
be defined on
![]()