Reporting estimate 56 to 54 we get
I J , n, q ≤ C
X
k≤k
n
∆b
1
k
1 −qα
E |X
n ,k
|
q
≤ X
k≤k
n
σ
−2qα n
,k
E |X
n ,k
|
q
and substituting this to inequality 53 we get Π
1
J , n; ǫ ≤ C
1
ǫ
−q
2
−J qα+1−q2
+ C
2
X
k≤k
n
σ
−2qα n
,k
E |X
n ,k
|
q
. Thus 51 follows from 10, and condition ii holds.
5.2 Proof of the theorem 13
It suffices to check that 50 and 51 hold. Proof of 50 Define:
S
n ,τ
k =
X
1≤ j ≤k
X
n , j ,τ
, S
′
n ,τ
k =
X
1≤ j ≤k
X
n , j ,τ
− E X
n , j ,τ
. 57
and A
n
= ½
max
1≤k≤k
n
|X
k
| ≤ τσ
2α n
,k
¾ .
Then the we can estimate the probability in 50 by P
max
1≤k≤k
n
|∆
1 k
1
S
n
k|
∆b
1
k
1 α
ǫ =: Π
1
n, ǫ ≤ Π
1
n, ǫ, τ + PA
c n
where Π
1
n, ǫ, τ = P max
1≤k≤k
n
|∆
1 k
1
S
n ,τ
k|
∆b
1
k
1 α
ǫ .
58 Due to 14 the probability PA
c n
tends to zero so we need only to study the asymptotics of Π
1
n, ǫ, τ.
Recall the definition 57. Using the splitting ∆
1 k
1
S
n ,τ
k = ∆
1 k
1
S
′
n
,τ
k + E ∆
1 k
1
S
n ,τ
k,
let us begin with some estimate of the expectation term, since X
n , j ,τ
are not centered. We have
E |X
n , j ,τ
| ≤ E
12
X
2
n , j
P
12
|X
n , j
| τσ
2α n
, j
2278
By applying Cauchy inequality we get max
1≤k≤k
n
|E ∆
1 k
1
S
n ,τ
k|
∆b
1
k
1 α
≤ max
1≤k
1
≤k
1
n
P
k
n ,2:d
k
2:d
=1
E |X
n , j ,τ
| ∆b
1
k
1 α
≤ max
1≤k
1
≤k
1
n
∆b
1
k
1 12
P
k
n ,2:d
k
2:d
=1
P|X
n ,k
| τσ
2α n
,k
12
∆b
1
k
1 α
≤ max
1≤k
1
≤k
1
n
∆b
1
k
1 12−α
X
1≤k≤k
n
P|X
n ,k
| τσ
2α n
,k
12
.
Due to 9 and 14 the last expression is bounded by ǫ2 for n ≥ n , where n
depends on ǫ and
τ. Thus for n ≥ n we have Π
1
n, ǫ, τ ≤ Π
′ 1
n, ǫ, τ, where
Π
′ 1
n, ǫ, τ = P max
1≤k≤k
n
|∆
1 k
1
S
′
n ,τ
k|
∆b
1
k
1 α
ǫ2 59
Since Var X
n ,k,τ
≤ E X
2
n ,k,τ
≤ E X
2
n ,k
= σ
2 n
,k
, using Markov, Doob and Rosenthal inequalities for q 112 − α we get
Π
′ 1
n, ǫ, τ ≤
k
1 n
X
k=1
ǫ2
−q
∆b
1
k
−qα
E |∆
1 k
S
′
n ,τ
k
n
|
q
≤ c
k
1 n
X
k=1
ǫ2
−q
∆b
1
k
−qα
∆b
1
k
q2
+
k
n ,2:d
X
k
2:d
=1
E |X
n ,k,τ
|
q
≤ cǫ2
−q k
1 n
X
k=1
∆b
1
k
q12−α
+ X
1≤k≤k
n
σ
−2qα n
,k
E |X
n ,k,τ
|
q
. Note that this estimate holds for each τ 0. Combining all the estimates we get
∀τ 0, lim sup
mn→∞
Π
1
n, ǫ ≤ c lim sup
mn→∞
X
1≤k≤k
n
σ
−2qα n
,k
E |X
n ,k,τ
|
q
. with the constant c depending only on q. By letting τ → 0 due to 16, 50 follows.
Proof of 51 Introduce similar definitions ψ
n ,τ
r, r
−
and ψ
′ n
,τ
r, r
−
by exchanging variables X
n ,k
with variables X
n ,k,τ
and X
′
n ,k,τ
:= X
n ,k,τ
− E X
n ,k,τ
respectively. Similar to the proof of 50 we get that we need only to deal with asymptotics of Π
2
J , n, ǫ, τ, where
Π
2
J , n, ǫ, τ = P
sup
j≥J
2
α j
max
r∈D
j
ψ
n ,τ
r, r
−
ǫ .
2279
Again we need to estimate the expectation term. We have sup
j≥J
2
α j
max
r∈D
j
max
1
2:d
≤k