(Convergence lemma
for family of complex numbers) Let
be a family of complex numbers such that
1.
,
,
2.
for a constant
independent of
,
3.
.
Then
Proof
We
calculate
All the potential difficulties with the above are ovecome by noting that the
are small starting from some
according to the condition 1.
Proposition
(Liapounov CLT) Let
is a family of r.v. such
that
Then
Proof
It suffices to establish
that
because then the statement would follow from the proposition
(
Convergence of pm and chf 2
).
To prove that
we verify the conditions of the proposition
(
Convergence lemma
for family of complex numbers
) pointwise in
for
:
We substitute the Taylor decomposition of
around
in the following
form:
Hence
Since
we have
Then by the proposition (
Liapounov
inequality
),
Hence,
The
condition
is verified in a similar manner with the use of
.