Ahlfors-Type Theorem for Hausdorff Measures
Suppose that Δ ⊂ C is a domain, f is an analytic function in Δ, D = f (Δ) is considered as a Riemann surface. Put l R = { z ∈ Δ : | f ( z )| = R }. Let E ⊂ Δ be a closed set. Put h α , β ( r ) = r α | ln r | β , 0 < α < 1, 0 < β < 1. Let Λ α , β (·), Λ α +1, β (·) be the Hausdorff measur...
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Veröffentlicht in: | Journal of mathematical sciences (New York, N.Y.) N.Y.), 2024, Vol.284 (6), p.880-893 |
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Sprache: | eng |
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Zusammenfassung: | Suppose that Δ ⊂
C
is a domain,
f
is an analytic function in Δ,
D
=
f
(Δ) is considered as a Riemann surface. Put
l
R
= {
z
∈ Δ : |
f
(
z
)| =
R
}. Let
E
⊂ Δ be a closed set. Put
h
α
,
β
(
r
) =
r
α
| ln
r
|
β
, 0 <
α
< 1, 0 <
β
< 1. Let Λ
α
,
β
(·), Λ
α
+1,
β
(·) be the Hausdorff measures with respect to the functions
h
α
,
β
,
h
α
+1,
β
. Assume that Λ
α
+1,
β
(
E
) < ∞. We introduce the sets
l
R
,
ε
= {
z
∈
l
R
: dist(
z
,
∂
Δ) ≥
ε
, |
z
| ≤
1
ε
} and
T
R
,
ε
=
f
(
l
R
,
ε
∩
E
),
T
R
,
ε
⊂
D
. Put
G
ε
R
=
0
i
f
Λ
α
,
β
T
R
,
ε
=
0
o
r
Λ
α
,
β
T
R
,
ε
=
∞
,
Λ
α
,
β
1
+
α
α
E
∩
l
R
,
ε
Λ
α
,
β
1
α
T
R
,
ε
i
f
0
<
Λ
α
,
β
T
R
,
ε
<
∞
.
Define the upper Lebesgue integral
∫
∞
∗
0
g
dm for a function
g
,
g
(
x
)≥0,
x
> 0 in the following way: let
U
(
y
)
=
def
{
x
> 0 :
g
(
x
) >
y
},
H
(
y
) =
m
*
U
(
y
). Then put
∫
∞
∗
0
g
dm
=
def
∫
∞
0
H
y
d
y
.
We prove the following result.
Theorem
. The condition Λ
α
,
β
(
T
R
,
ε
) < ∞ is fulfilled for almost all
R
with respect to the 1-Lebesgue measure and
∫
∞
∗
0
lim
̲
ε
→
+
0
G
ε
R
d
R
≤
2
Λ
1
+
α
,
β
E
. |
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ISSN: | 1072-3374 1573-8795 |
DOI: | 10.1007/s10958-024-07395-4 |