ĐẠI HỌC THÁI NGUYÊN
TRƯỜNG ĐẠI HỌC SƯ PHẠM
ĐỖ THỊ HỒNG NGA
XÂY DỰNG ĐƯỜNG CONG CHỈNH HÌNH
VỚI MỘT TẬP VÔ HẠN SỐ KHUYẾT
LUẬN VĂN THẠC SĨ TOÁN HỌC
THÁI NGUYÊN – 2008
ĐẠI HỌC THÁI NGUYÊN
TRƯỜNG ĐẠI HỌC SƯ PHẠM
ĐỖ THỊ HỒNG NGA
XÂY DỰNG ĐƯỜNG CONG CHỈNH HÌNH
VỚI MỘT TẬP VÔ HẠN SỐ KHUYẾT
Chuyên ngành: GIẢI TÍCH
Mã số: 60.46.01
LUẬN VĂN THẠC SĨ TOÁN HỌC
Người hướng dẫn khoa học:
TS. TẠ THỊ HOÀI AN
THÁI NGUYÊN – 2008
f
T (f, a, r)
N(f, a, r) f a r
m(f, a, r) a f
a ∈ C ∪ {∞}
a N(f, a, r)
m(f, a, r)
f a
δ(f, a) := lim inf
r→∞
{1 −
N(f, a, r)
T (f, a, r)
}.
a f δ(f, a) > 0
a∈C∪{∞}
δ(f, a) 2.
[0, 1].
1 ≤ i ≤ N ≤ ∞, {δ
i
}
0 < δ
i
≤ 1,
i
δ
i
≤ 2.
a
i
, C ∪ {∞}.
f C δ(f, a
i
) = δ
i
, δ(f, a) = 0 a /∈ {a
i
}?
C P
1
(C)
P
n
(C) n 2
f : C → P
n
(C) H
1
, . . . , H
q
P
n
(C)
q
j=1
δ(H
j
, f) n + 1.
n 2
a
a
f R r < R
n(f, ∞, r), n(f, ∞, r)),
f r.
a ∈ C
n(f, a, r) = n
1
f − a
, ∞, r
,
n(f, a, r) = n
1
f − a
, ∞, r
.
N(f, a, r),
N(f, a, r) f a
N(f, a, r) = n(f, a, 0) log r +
r
0
n(f, a, t) − n(f, a, 0)
dt
t
,
N(f, a, r) = n(f, a, 0) log r +
r
0
n(f, a, t) − n(f, a, 0)
dt
t
).
a = 0
N(f, 0, r) = (
+
0
f) log r +
z∈D(r)
z=0
(
+
z
f) log |
r
z
|,
D(r) r
+
z
f = max{0,
z
f}
m(f, a, r) f a ∈ C
m(f, a, r) =
2π
0
log
+
1
f(re
iθ
) − a
dθ
2π
,
m(f, ∞, r) =
2π
0
log
+
| f(re
iθ
) |
dθ
2π
,
log
+
x = max{0, log x}.
m(f, ∞, r) log |f| |z| = r
T (f, a, r) f a ∈ C
T (f, a, r) = m(f, a, r) + N(f, a, r),
T (f, r) = m(f, ∞, r) + N(f, ∞, r).
T (f, a, r) ≥ N(f, a, r) + O(1),
O(1) r → ∞
f
ρ(f) = lim sup
r→∞
log T (r, f)
log r
.
ρ(f) = ∞ f 0 < ρ(f) < ∞ f
0 < ρ(f) < ∞
C = lim sup
r→∞
T (r, f)
r
ρ
.
f C = ∞ 0 < C < ∞,
C = 0.
f T (f, r) = O(log r),
f = e
z
T (f, r) = r/π + O(1) e
z
e
e
z
f(z) ≡ 0, ∞
D = {|z| ≤ R} 0 < R < ∞ a
µ
, µ = 1, , M
f D,
b
ν
, (ν = 1, 2, , N) f D,
z = re
iθ
∈ D f(z) = 0, f(z) = ∞
log |f(z)| =
1
2π
2π
0
log
f(Re
iφ
)
R
2
− r
2
R
2
− 2Rr cos(θ − φ) + r
2
dφ+
+
M
µ=1
log
R(z − a
µ
)
R
2
− a
µ
z
−
N
ν=1
log
R(z − b
ν
)
R
2
− b
ν
z
.
f(z)
{|z| ≤ R} z = 0
log |f(0)| =
1
2π
2π
0
log
f(Re
iϕ
)
dϕ.
f(z) = 0 D log f(z) D.
log f(0) =
1
2πi
|z|=R
log f(z)
dz
z
=
1
2π
2π
0
log f(Re
iϕ
)dϕ.
log |f(0)| =
1
2π
2π
0
log
f(Re
iϕ
)
dϕ.
f(z)
{|z| ≤ R} z z = re
iθ
(0 < r < R)
{|ξ| R} → {ω 1}
z → 0
ξ = z → ω =
R (ξ − z)
R
2
− zξ
|ς| = R |ω| = 1
|ω| =
R |ξ − z|
|R
2
− zξ|
|ξ| = R ⇒ ξξ = |ξ|
2
= R
2
|ω| =
R |ξ − z|
ξξ − zξ
=
R |ξ − z|
|ξ|
ξ − z
= 1.
log f(z) |ξ| ≤ R
log f(z) =
1
2πi
|ξ|=R
log f(ς)
dξ
ξ − z
.
1
2πi
|ξ|=R
log f(ξ)
zdξ
R
2
− zξ
=
1
2πi
|ξ|=R
log f(ξ)
−dξ
ξ −
R
2
z
= 0.
|z| = |z| < R
R
2
z
> R
R
2
z
|ξ| ≤ R
log f(ξ)
1
ξ −
R
2
z
log f(z) =
1
2i
|ξ|=R
log f(ξ)
1
ξ − z
+
1
ξ −
R
2
z
dξ
=
1
2i
|ξ|=R
log f(ξ)
1
ξ − z
+
z
R
2
− zξ
dξ,
1
ξ − z
+
z
R
2
− zξ
=
R
2
− zξ + zξ − zz
(ξ − z) (R
2
− zξ)
=
R
2
− r
2
(ξ − z)
ξξ − zξ
=
R
2
− r
2
ξ |ξ − z|
2
.
ξ = Re
iϕ
= R cos ϕ + iR sin ϕ,
z = re
iθ
= r cos θ + ir sin θ,
ξ − z = (R cos ϕ − r cos θ) + i (R sin ϕ − r sin θ) ,
|ξ − z|
2
= (R cos ϕ − r cos θ)
2
+ (R sin ϕ − r sin θ)
2
= R
2
+ r
2
− 2Rr cos(ϕ − θ).
log f(z) =
1
2π
2π
0
log f(Re
iφ
)
R
2
− r
2
R
2
− 2Rr cos(θ − ϕ) + r
2
dϕ.
log |f(z)| =
1
2π
2π
0
log
f(Re
iϕ
)
R
2
− r
2
R
2
− 2Rr cos(θ − ϕ) + r
2
dϕ.
f(z) {|z| = R}
{|z| < R}
f(z) {|z| = R}
f(z) {z
k
} , {|ξ| = R}
z
k
j
z
k
0
∈ {|ξ| = R} f(z
k
j
) = 0, f = 0
f ≡ 0
{z
k
} ,
z
k
j
→ z
0
∈
{|ξ| = R}, z
0
f z
0
z
0
f z
0
z
k
j
→ z
0
z
0
z
k
j
f
f(z) {|z| = R} .
Z
0
k f(ξ), Z
0
∈ ∂D.
Z
0
,
f(ξ) = a(ξ − Z
0
)
k
+ . . . , a = 0.
log |f(ξ)| = k log |ξ − Z
0
| + o(|ξ − Z
0
|).
C
δ
Z
0
δ |ξ| = R
C
δ
, f
|ξ| = R
C
δ
1
2π
|ξ−Z
0
|=δ
log |f(ξ)| |dξ| .
|ξ−Z
0
|=δ
log |f(ξ)| |dξ| = C
δ
. log δ.δ.
C
δ
1
2π
|ξ−Z
0
|=δ
log |f(ξ)| |dξ| ≈ A log δ.δ.
δ → 0
C
δ
1
2π
|ξ−Z
0
|=δ
log |f(ξ)| |dξ| → 0.
f(z)
|z| ≤ R.
ψ(z) = f(z)
N
γ=1
R(z−b
γ
)
R
2
−b
γ
z
M
µ=1
R(z−a
µ
)
R
2
−a
µ
z
.
ψ(z) |ξ| R
ψ(z
0
) = 0 f(z
0
) = 0. ψ(ξ)
ψ(ξ)
log |ψ(z)| =
1
2π
2π
0
log
ψ(Re
iϕ
)
R
2
− r
2
R
2
− 2Rr cos(ϕ − θ) + r
2
dϕ.
log |f(z)| +
N
γ=1
log
R(z − b
γ
)
R
2
− b
γ
z
−
M
µ=1
log
R(z − a
µ
)
R
2
− a
µ
z
=
1
2π
2π
0
log
ψ(Re
iϕ
)
R
2
− r
2
R
2
− 2Rr cos(ϕ − θ) + r
2
dϕ.
|z| = R
R(z−b
γ
)
R
2
−b
γ
z
= 1,
R(z−a
µ
)
R
2
−a
µ
z
= 1.
|z| = R |ψ(z)| = |f(z)| .
log |f(z)| +
N
γ=1
log
R(z − b
γ
)
R
2
− b
γ
z
−
M
µ=1
log
R(z − a
µ
)
R
2
− a
µ
z
=
1
2π
2π
0
log
f(Re
iϕ
)
R
2
− r
2
R
2
− 2Rr cos(ϕ − θ) + r
2
dϕ.
log |f(z)| =
1
2π
2π
0
log
f(Re
iϕ
)
R
2
− r
2
R
2
− 2Rr cos(ϕ − θ) + r
2
dϕ
+
M
µ=1
log
R(z − a
µ
)
R
2
− a
µ
z
−
N
γ=1
log
R(z − b
γ
)
R
2
− b
γ
z
.
f a
m(f, a, r) + N(f, a, r) = T (f, r) − log |f(0) − a| + (a, r),
(a, r) ≤ log a + log 2.
T (f, a, r) = T (f, r) + O(1),
O(1) r → ∞.
a
f(z)
C a
1
, . . . , a
q
q
(q − 2)T (f, r) ≤
q
i=1
N(f, a
i
, r) − N (f, r) + O
log T (r, f)
,
r → ∞
N (f, r) = N(f
, 0, r) + 2N(f, ∞, r) − N(f
, ∞, r).
f a
δ(f, a) = lim inf
r→∞
1 −
N(f, a, r)
T (f, r)
.
f a
θ(f, a) = lim inf
r→∞
N(f, a, r) − N(f, a, r)
T (f, r)
.
f a
Θ(f, a) = θ(f, a) + δ(f, a) = lim inf
r→∞
1 −
N(f, a, r)
T (f, r)
.
a ∈ C ∪{∞} a
f δ(f, a) > 0; a
f δ(f, a) = 1.
a ∈ C ∪ {∞},
0 ≤ δ(f, a), 0 ≤ θ(f, a), Θ(f, a) = θ(f, a) + δ(f, a) ≤ 1.
f a
1
, . . . , a
q
C ∪ {∞},
S(f, {a
j
}
q
j=1
, r) = (q − 2)T (f, r) −
q
j=1
N(f, a
j
, r) + N (f, r).
f(z) C
a
1
, . . . , a
q
C ∪ {∞}.
lim inf
r→∞
S(f, {a
j
}
q
j=1
, r)
T (f, r)
≤ 0.
f(z) |z| < R
0
a δ(f, a) > 0 θ(f, a) > 0
a∈C∪{∞}
{δ(f, a) + θ(f, a)} =
a∈C∪{∞}
Θ(f, a) 2.
q a
1
, a
2
, , a
q
C ∪ {∞}.
q
j=1
(δ(f, a
j
) + θ(f, a
j
))
= lim inf
r→∞
qT(f, r) −
q
j=1
N(f, a
j
, r) +
q
j=1
N(f, a
j
, r) −
q
j=1
¯
N(f, a
j
, r)
T (f, r)
.
N(f, a
j
, r) −
¯
N(f, a
j
, r) f = a
q
j=1
N(f, a
j
, r) −
q
j=1
¯
N(f, a
j
, r) ≤ N (f, r) + n (f, 0) log
+
1
r
.
q
j=1
(δ(f, a
j
) + θ(f, a
j
)) ≤ lim inf
r→∞
qT(f, r) −
q
j=1
N(f, a
j
, r) + N (f, r)
T (f, r)
= 2 + lim inf
r→∞
(q − 2)T (f, r) −
q
j=1
N(f, a
j
, r) + N (f, r)
T (f, r)
= 2 + lim inf
r→∞
S(f, {a
j
}
q
j=1
, r)
T (f, r)
≤ 2,
k a
Θ(f, a) ≥ 1/k.
{a : Θ(f, a) ≥ 0} = ∪
∞
k=1
{a : Θ(f, a) ≥ 1/k},
a
f
a∈C
Θ(f, a) 1.
f Θ(f, ∞) = 1.
f(z)
∞ f
f f(z)
∞
N(f, 0, r) = 0; N(f, 1, r) = 0; N(f, ∞, r) = 0.
Θ(f, 0) = 0; Θ(f, 1) = 1; Θ(f, ∞) = 1.
a∈C∪{∞}
Θ(f, a) 2,
f(z)
1 ≤ i ≤ N ≤ ∞, {δ
i
}
{θ
i
}
0 < δ
i
+ θ
i
≤ 1,
i
(δ
i
+ θ
i
) ≤ 2.
a
i
, 1 ≤ i < N C ∪ {∞}.
f C
δ(f, a
i
) = δ
i
, θ(f, a
i
) = θ
i
, 1 ≤ i < N
δ(f, a) = θ(f, a) = 0 a /∈ {a
i
}?
(C
∗
)
n+1
= C
n+1
\ (0, . . . , 0)
(C
∗
)
n+1
(x
0
, . . . , x
n
) ∼ (y
0
, . . . , y
n
)
0 = λ ∈ C (x
0
, . . . , x
n
) = λ(y
0
, . . . , y
n
).
n C P
n
(C) P
n
(C
∗
)
n+1
∼ . P
n
= (C
∗
)
n+1
/ ∼ .
P
n
(x
0
, . . . , x
n
)
∼ . P P
n
P = (x
0
: · · · : x
n
) (x
0
: · · · : x
n
)
P
f = (f
0
: f
1
: · · · : f
n
) : C → P
n
(C)
f
i
C
f = (
f
0
,
f
1
, . . . ,
f
n
)
f
i
(
f
0
,
f
1
, . . . ,
f
n
)
f
f : C → P
n
(C) f = (f
0
, . . . , f
n
)
f f
0
, . . . , f
n
C
f(z) = (|f
0
(z)|
2
+ · · · + |f
n
(z)|
2
)
1
2
.
T
f
(r)
T (r, f) =
1
2π
2π
0
log f(re
iθ
)dθ.
Q d n+1 m(r, Q, f)
f Q
m(r, Q, f) =
1
2π
2π
0
log
f(re
iθ
)
d
|Q ◦ f(re
iθ
)|
dθ.
n(r, Q, f), n(r, Q, f)
Q ◦ f |z| ≤ r
N(r, Q, f),
N(r, Q, f)),
N(r, Q, f) =
r
0
n(t, Q, f) − n
f
(0, Q)
t
dt − n(0, Q, f) log r,
N(r, Q, f) =
r
0
n(t, Q, f) − n(0, Q, f)
t
dt − n(0, Q, f) log r).
f : C → P
n
(C)
Q d P
n
(C)
Q ◦ f(C) ≡ 0 0 < r < ∞
m(r, Q, f) + N(r, Q, f) = dT (r, f) + O(1),
O(1) r
f : C → P
n
(C)
L
1
, . . . , L
q
P
n
(C)
2π
0
max
K
log
j∈K
f(re
iθ
)L
j
|L
j
(f)(re
iθ
)|
dθ
2π
(n + 1)T (r, f) + o(T (r, f)),
K {1, . . . , q}
L
j
, j ∈ K L
j
L
j
a
a
a
0
z
0
+ · · · + a
n
z
n
= 0
H P
n
.
H a = (a
0
, . . . , a
n
) ∈ C
n+1
\ {(0, , 0)}
P
n
C
n+1
a = (|a
0
|
2
+ + |a
n
|
2
)
1
2
,
(a, f) = a
0
f
0
+ + a
n
f
n
,
(a, f(z)) = a
0
f
0
(z) + + a
n
f
n
(z),
f := (f
0
, . . . , f
n
) : C → P
n
(C)
a ∈ C
n+1
− {0}
m(r, a, f) =
1
2π
2π
0
log
a
f(re
iθ
)
|(a, f(re
iθ
))|
dθ,
N(r, a, f) = N(r, 1/(a, f)).
f := (f
0
, . . . , f
n
) : C → P
n
(C)
C f
0
, , f
n
C
f := (f
0
, . . . , f
n
) : C → P
n
(C)
f lim
r→∞
T (r,f)
log r
= ∞.
ρ(f) = lim sup
r→∞
log T (r, f)
log r
f.
f : C → P
n
(C)
a ∈ C
n+1
− {0}
T (r, f) = m(r, a, f) + N(r, a, f) + O(1),
O(1)
f : C → P
n
(C) a ∈ C
n+1
−{0}
δ(f, a) = 1 − lim sup
r→∞
N(r, a, f)
T (r, f)
= lim inf
r→∞
m(r, a, f)
T (r, f)
f a.
0 δ(f, a) 1.
a ∈ C
n+1
− {0} a
f δ(f, a) > 0; a
f δ(f, a) = 1.
X C
n+1
− {0} , N
N n X N
#X N + 1 N + 1 X C
n+1
.
X X n
N
N = n N > n
f : C → P
n
(C) q
a
1
, , a
q
X N
q
j=1
δ(a
j
, f) 2N − n + 1,
2N − n + 1 q ∞.
{η
v
}
η
v
> 0,
∞
v=1
η
v
= 1, η
0
= η
1
.
θ
0
= 0, θ
k
= π
k−1
v=0
η
v
, (k = 1, 2, 3, ).
{θ
k
}
π
∞
v=0
η
v
= πη
0
+ π
∞
v=1
η
v
2π,
k → ∞.
k 1, z = re
iθ
θ
θ
k
−
1
3
πη
k
< θ θ
k
+
1
3
πη
k
.
cos(θ
v
− θ) cos(
2
3
πη
k
) ν = k.
e
ze
−iθ
v
e
r cos
2
3
πη
k
ν = k.
v < n
θ − θ
v
(θ
n
− θ
n−1
) −
1
3
πη
n
= π(η
n−1
−
1
3
η
n
)
2
3
πη
n
,
v > n
θ
v
− θ (θ
n+1
− θ
n
) −
1
3
πη
n
=
2
3
πη
n
.
|θ
v
− θ|
2
3
πη
n
(mod2π), (v = n).
cos(θ
v
− θ) cos(
2
3
πη
k
).
e
ze
−iθ
v
e
re
i(θ−θ
v)
= e
r cos(θ−θ
v
)
e
r cos
2
3
πη
k
, (v = k).