设为首页
加入收藏
期刊导航
网站地图
首页
期刊
数学与物理
地球与环境
信息通讯
经济与管理
生命科学
工程技术
医药卫生
人文社科
化学与材料
会议
合作
新闻
我们
招聘
千人智库
我要投稿
办刊
期刊菜单
●领域
●编委
●投稿须知
●最新文章
●检索
●投稿
文章导航
●Abstract
●Full-Text PDF
●Full-Text HTML
●Full-Text ePUB
●Linked References
●How to Cite this Article
PureMathematics
n
Ø
ê
Æ
,2023,13(1),74-80
PublishedOnlineJanuary2023inHans.https://www.hanspub.org/journal/pm
https://doi.org/10.12677/pm.2023.131008
²
¡
þ
±~
°
ü
«
•
Ý
4
à
-
‚
6
ëëë
¬¬¬
©©©
∗
§§§
ÜÜÜLLL
H
“
‰
Œ
Æ
§
H
&
²
Â
v
F
Ï
µ
2022
c
12
22
F
¶
¹
^
F
Ï
µ
2023
c
1
21
F
¶
u
Ù
F
Ï
µ
2023
c
1
29
F
Á
‡
©
Ì
‡
ï
Ä
²
¡
þ
ü
«
•
Ý
4
à
-
‚
6
,
3ù
ü
«
6
e
,
X
J
Ð
©
4
à
-
‚
´
2
Â
~
°
-
‚
,
@
o
3ù
ü
«
6
e
u
Ð
,
-
‚
E,
±
2
Â
~
°
,
¿
…
°
Ý
†
Ð
©
-
‚
°
Ý
ƒ
.
A
O
/
,
X
J
Ð
©
-
‚
´
~
°
-
‚
,
@
o
3ù
ü
«
6
e
-
‚
©
ª
±~
°
,
¿
…
°
Ý
†
Ð
©
-
‚
°
Ý
ƒ
"
'
…
c
•
Ý
6
§
2
Â
°
Ý
¼
ê
§
~
°
-
‚
Closed-ConvexCurvilinearFlowswith
TwoKindsofLengthPreservingConstant
WidthonthePlane
HuiwenZhao
∗
,ZeyuanZhang
YunnanNormalUniversity,KunmingYunnan
Received:Dec.22
nd
,2022;accepted:Jan.21
st
,2023;published:Jan.29
th
,2023
∗
Ï
Õ
Š
ö
"
©
Ù
Ú
^
:
ë
¬
©
,
ÜL
.
²
¡
þ
±~
°
ü
«
•
Ý
4
à
-
‚
6
[J].
n
Ø
ê
Æ
,2023,13(1):74-80.
DOI:10.12677/pm.2023.131008
ë
¬
©
§
ÜL
Abstract
Inthispaper,wemainlystudytwokindsoflengthpreservingclosedconvexcurve
flowsontheplane.Underthesetwokindsofflows,iftheinitialclosedconvexcurve
isageneralizedconstantwidthcurve,thenthecurvewillstillmaintainageneralized
constantwidthunderthesetwokindsofflows,andthewidthisequaltothewidth
oftheinitialcurve.Especially,iftheinitialcurveisaconstantwidthcurve,thenthe
curvewillalwaysmaintainaconstantwidthunderthesetwokindsofflows,andthe
widthisequaltothewidthoftheinitialcurve.
Keywords
PreserveLengthFlow,GeneralizedWidthFunction,ConstantWidthCurve.
Copyright
c
2023byauthor(s)andHansPublishersInc.
ThisworkislicensedundertheCreativeCommonsAttributionInternationalLicense(CCBY4.0).
http://creativecommons.org/licenses/by/4.0/
1.
Ú
ó
9
Ì
‡
(
J
²
¡
þ
-
‚
6
ï
Ä
´
A
Û
©
Û
Æ
˜
‡
©
|
,
C
c
5
,
Ñ
u
ˆ
«
Ô
n
y–
Ú
y
¢
¯
K
I
‡
,
-
‚
É
å
K
•
)
ƒ
A
6
5
Ÿ
•
5
•
õ
'
5
Ú
ï
Ä
.
3
1984
c
§
GageHamilton
3
©
[1]
¥
ï
Ä
Í
¶
-
‚
Â
6
(
∂F
(
u,t
)
∂t
=
k
(
u,t
)
N
(
u,t
)
F
(
u,
0)=
F
0
(
u
)
(1.1)
ª
¥
F
(
u,t
):[
a,b
]
×
[0
,
∞
)
→R
2
´
˜
x
²
¡
4
-
‚
,
k
(
u,t
)
´
ƒ
é
-
Ç
,
N
(
u,t
)
´
ü
S
{
•
þ
.
y
²
Ð
©
-
‚
•
²
¡
{
ü
4
à
-
‚
ž
,
K3
ü
z
L
§
¥
˜
†
±
à
5
,
…
3
k
•
ž
m
S
Â
¤
˜
‡
:
.
©
[2–5]
ï
Ä
o
«
Ø
Ó
a
.
•
Ý
6
.
©
Ì
‡
ï
Ä
„
Ý
¼
ê
¥
¹
k
|
¼
ê
ü
«
•
Ý
-
‚
6
,
•
Ä
X
J
Ð
©
-
‚
´
°
Ý
•
ω
m
(
θ,
0)
2
Â
~
°
-
‚
,
@
o
-
‚
3ù
ü
«
6
e
u
Ð
,
´
Ä
±
2
Â
~
°
,
¿
…
°
Ý
†
Ð
©
-
‚
°
Ý
ƒ
?
DOI:10.12677/pm.2023.13100875
n
Ø
ê
Æ
ë
¬
©
§
ÜL
Ä
k
3
2010
c
,
Š
Ÿ
p
3
©
[5]
¥
ï
Ä
L
„
Ý
¼
ê
•
±
e
(
-
‚
6
.
F
0
´
Ð
©
4
à
-
‚
,
F
(
u,t
):
S
1
×
[0
,T
)
→
R
2
´
˜
x
²
¡
1
w
-
‚
.
F
(
u,t
)
÷
v
±
e
ü
z
•
§
∂F
∂t
=
p
(
u,t
)
−
1
k
(
u,t
)
N
(
u,t
)
F
(
u,
0)=
F
0
(
u
)
(1.2)
Ù
¥
p
=
p
(
u,t
)
•
ü
z
-
‚
|
¼
ê
,
N
=
N
in
(
u,t
)
•
ü
z
-
‚
ü
S
{
•
þ
,
k
(
u,t
)
•
ü
z
-
‚
-
Ç
.
l
©
[5]
¥
Œ
±
µ
F
0
´
²
¡
þ
Ð
©
4
à
-
‚
,
-
‚
F
(
u,t
)
3
6
(1.2)
e
ü
z
,
3
ü
z
L
§
¥
-
‚
X
(
u,t
)
±
4
à
5
ØC
,
…-
‚
3
u
Ð
L
§
¥
C
5
,
•
Ý
L
(
t
)
±
ØC
,
¡
È
A
(
t
)
O
Œ
,
ž
m
ª
u
Ã
¡
ž
,
3
C
∞
Ý
þ
e
Â
ñ
k
•
.
du
U
C
u
Ð
•
§
ƒ
•
©
þ
•
K
•
-
‚
ë
ê
L
«
,
Ø
¬
K
•
u
Ð
-
‚
A
Û
/
G
,
¤
±
·
‚
À
J
·
ƒ
•
©
þ5
{
z
-
‚
1
•
A
Û
©
Û
,
Ï
d
,
3
©
[5]
¥
Œ
±
•
Ä
X
e
†
ª
(1.2)
d
u
Ð
¯
K
µ
∂F
∂t
=
p
(
u,t
)
−
1
k
(
u,t
)
N
(
u,t
)
−
1
k
∂
(
p
(
u,t
)
−
1
k
(
u,t
)
)
∂s
T
(
u,t
)
F
(
u,
0)=
F
0
(
u
)
(1.3)
Ù
¥
T
(
u,t
)
•
ü
ƒ
•
þ
.
ƒ
3
2017
c
,
À
(
Ú
‘
²
3
©
[6]
¥
•
ï
Ä
L
„
Ý
¼
ê
¥
¹
k
|
¼
ê
-
‚
6
.
F
0
´
Ð
©
4
à
-
‚
,
F
(
u,t
):
S
1
×
[0
,T
)
→
R
2
´
˜
x
²
¡
1
w
-
‚
.
F
(
u,t
)
÷
v
±
e
ü
z
•
§
∂F
∂t
=
p
(
u,t
)
−
α
L
(
t
)
2
π
+(1
−
α
)
2
A
(
t
)
L
(
t
)
N
(
u,t
)
F
(
u,
0)=
F
0
(
u
)
(1.4)
Ù
¥
p
=
p
(
u,t
)
•
ü
z
-
‚
|
¼
ê
,
N
=
N
in
(
u,t
)
•
ü
z
-
‚
ü
S
{
•
þ
,
L
(
t
)
•
ü
z
-
‚
•
Ý
,
A
(
t
)
•
ü
z
-
‚
¡
È
,0
≤
α
≤
1
§
3
α
Ø
Ó
Š
œ
¹
e
,
ü
z
-
‚
•
Ý
Ú
¡
È
ü
N
5
Ø
Ó
,
©
Ì
‡
ï
Ä
α
=1
œ
¹
,
=
∂F
∂t
=
p
(
u,t
)
−
L
(
t
)
2
π
N
(
u,t
)
F
(
u,
0)=
F
0
(
u
)
.
(1.5)
l
©
[6]
¥
Œ
±
µ
F
0
´
²
¡
þ
Ð
©
4
à
-
‚
,
-
‚
F
(
u,t
)
3
6
(1.5)
e
ü
z
,
3
ü
z
L
§
¥
-
‚
X
(
u,t
)
±
4
à
5
ØC
,
…-
‚
3
u
Ð
L
§
¥
C
5
,
•
Ý
L
(
t
)
±
ØC
,
¡
È
A
(
t
)
O
Œ
,
ž
m
ª
u
Ã
¡
ž
,
3
C
∞
Ý
þ
e
Â
ñ
k
•
.
du
U
C
u
Ð
•
§
ƒ
•
©
þ
•
K
•
-
‚
ë
ê
L
«
,
Ø
¬
K
•
u
Ð
-
‚
A
Û
/
G
,
¤
±
·
‚
À
J
·
ƒ
•
©
þ5
{
z
-
‚
1
•
A
Û
©
Û
,
Ï
d
,
3
©
[6]
¥
Œ
±
•
Ä
X
e
†
ª
(1.5)
d
u
Ð
¯
K
µ
∂F
∂t
=
p
(
u,t
)
−
L
(
t
)
2
π
+
N
(
u,t
)
−
1
k
∂
(
p
(
u,t
)
−
L
(
t
)
2
π
)
∂s
T
(
u,t
)
F
(
u,
0)=
F
0
(
u
)
(1.6)
DOI:10.12677/pm.2023.13100876
n
Ø
ê
Æ
ë
¬
©
§
ÜL
©
Ì
‡
½
n
Q
ã
X
e
:
½
n
1.1
X
J
Ð
©
4
à
-
‚
´
°
Ý
•
ω
m
(
θ,
0)
2
Â
~
°
-
‚
,
@
o
3
6
(1.3)
e
u
Ð
,
-
‚
±
2
Â
~
°
,
¿
…
°
Ý
†
Ð
©
-
‚
°
Ý
ƒ
.
½
n
1.2
X
J
Ð
©
4
à
-
‚
´
°
Ý
•
ω
m
(
θ,
0)=
m
·
L
(0)
2
π
2
Â
~
°
-
‚
,
@
o
3
6
(1.6)
e
u
Ð
,
-
‚
±
2
Â
~
°
,
¿
…
°
Ý
†
Ð
©
-
‚
°
Ý
ƒ
.
©
(
S
ü
:
©
©
•
n
‡
Ü
©
,
1
˜
Ü
©
•
Ú
ó
Ú
Ì
‡
½
n
,
ù
Ü
©
Ì
‡
0
„
Ý
¼
ê
¥
¹
k
|
¼
ê
ü
«
•
Ý
-
‚
6
ï
Ä
µ
9
(
J
,
Ó
ž
‰
Ñ
©
ï
Ä
8
Ú
Ì
‡
(
J
;
1
Ü
©
•
ý
•
£
,
ù
Ü
©
Ì
‡
½
Â
|
¼
ê
!
°
Ý
¼
ê
±
9
2
Â
°
Ý
¼
ê
,
±
9
ü
‡
-
‡
Ú
n
;
1
n
Ü
©
•
Ì
‡
½
n
y
²
,
ù
Ü
©
Ì
‡
|
^
Š
Ÿ
p
3
©
[5]
¥
9
À
(
Ú
‘
²
3
©
[6]
¥
ï
Ä
²
¡
þ
ü
«
•
Ý
4
à
-
‚
6
‰
Ñ
©
Ì
‡
½
n
y
²
.
2.
ý
•
£
½
Â
2.1[7]
à
8
|
¼
ê
:
K
•
k
.
4
à
8
,
3
²
¡
þ?
¿
À
‹
I
X
x
0
y
.
g
:
0
Ú
‚
0
R
.
Š
R
†
u
0
R
…
†
K
ƒ
‘
?
¿˜
†
‚
G
1
(
P
1
,θ
).
8
p
1
þ(
.
•
p
,
=
p
=
sup
{
p
1
:
G
1
(
p
1
,θ
)
∩
K
6
=
∅}
,
(2.1)
Ù
¥
G
1
†
K
•
š
˜
L
«
G
1
†
K
ƒ
¿
g
.
†
(2.1)
ª
¥
p
ƒ
A
†
‚
G
(
p,θ
)
w
,
•
K
|
‚
,
¡
•
K
÷
θ
•
•
|
‚
.
¼
ê
p
(
θ
)
¡
•
à
8
K
|
¼
ê
.
½
Â
2.2[7]
°
Ý
¼
ê
:
Ú
?
¼
ê
ω
(
θ
)=
p
(
θ
)+
p
(
θ
+
π
)
,
(2.2)
w
,
,
ω
(
θ
)
´
é
u
•
•
θ
,
Ú
θ
+
π
ü
²
1
|
¼
ê
m
å
l
,
¡
•
à
8
K
÷
θ
•
•
°
Ý
,
¼
ê
ω
(
θ
)
¡
•
à
8
K
°
Ý
¼
ê
.
½
Â
2.3[8]
2
Â
°
Ý
¼
ê
:
é
u
ê
m
≥
2,
ω
(
θ
)=
p
(
θ
)+
p
(
θ
+
π
)
í
2
/
ª
•
µ
ω
m
(
θ
)=
p
(
θ
)+
p
θ
+
2
π
m
+
···
+
p
θ
+
2(
m
−
1)
π
m
(2.3)
Ï
•
1+cos
2
π
m
+
···
+cos
2(
m
−
1)
π
m
=0
,
sin
2
π
m
+
···
+sin
2(
m
−
1)
π
m
=0
¤
±
ω
m
(
θ
)
†
:
O
À
Ã
'
,
…
§
±
Ï
•
2
π
m
.
DOI:10.12677/pm.2023.13100877
n
Ø
ê
Æ
ë
¬
©
§
ÜL
Ú
n
2.1[5]
X
J
4
à
-
‚
F
(
u,t
)
U
ì
•
§
(1.2)
ü
z
,
K
k
p
t
=
1
k
−
p
(2.4)
Ú
n
2.2[6]
X
J
4
à
-
‚
F
(
u,t
)
U
ì
•
§
(1.5)
ü
z
,
K
k
p
t
=
L
2
π
−
p
(2.5)
3.
Ì
‡
½
n
y
²
½
n
1.1
y
²
d
p
+
p
θθ
=
1
k
(3.1)
2
d
Ú
n
2.1
Œ
p
t
=
p
θθ
(3.2)
qd
½
Â
2.3
Œ
∂ω
m
(
θ,t
)
∂t
=
∂
∂t
(
p
(
θ,t
))+
∂
∂t
p
θ
+
2
π
m
,t
+
···
+
∂
∂t
p
θ
+
2(
m
−
1)
π
m
,t
=
∂
2
p
(
θ,t
)
∂θ
2
+
∂
2
p
θ
+
2
π
m
,t
∂θ
2
+
···
+
∂
2
p
θ
+
2(
m
−
1)
π
m
,t
∂θ
2
=
∂
2
ω
m
(
θ,t
)
∂θ
2
(3.3)
X
J
Ð
©
-
‚
´
°
Ý
•
ω
m
(
θ,
0)
~
°
-
‚
,
@
o
k
ω
m
(
θ,t
)=
1
2
√
πt
Z
+
∞
−∞
ω
m
(
θ,
0)
e
−
(
θ
−
u
)
2
4
t
du
=
ω
m
(
θ,
0)(3.4)
=
3
u
Ð
¥
-
‚
2
Â
~
°
5
±
ØC
,
¿
…
°
Ý
†
Ð
©
-
‚ƒ
.
í
Ø
1[5]
A
O
/
,
m
=2
ž
,
X
J
Ð
©
-
‚
´
~
°
-
‚
,
@
o
-
‚
3
6
(1.3)
e
©
ª
±~
°
,
¿
…
°
Ý
ØC
.
½
n
1.2
y
²
d
½
Â
2.3
†
Ú
n
2.2
∂ω
m
(
θ,t
)
∂t
=
∂
∂t
(
p
(
θ,t
))+
∂
∂t
p
θ
+
2
π
m
,t
+
···
+
∂
∂t
p
θ
+
2(
m
−
1)
π
m
,t
=
L
(0)
2
π
−
p
(
θ,t
)+
L
(0)
2
π
−
p
θ
+
2
π
m
,t
+
···
+
L
(0)
2
π
−
p
θ
+
2(
m
−
1)
π
m
,t
=
m
·
L
(0)
2
π
−
ω
m
(
θ,t
)
.
(3.5)
DOI:10.12677/pm.2023.13100878
n
Ø
ê
Æ
ë
¬
©
§
ÜL
d
(3.5)
†
Ð
©
^
‡
(
∂ω
m
(
θ,t
)
∂t
=
m
·
L
(0)
2
π
−
ω
m
(
θ,t
)
ω
m
(
θ,
0)=
m
·
L
(0)
2
π
(3.6)
e
¡
)
•
§
(3.6),
Ä
k
-
ω
m
(
θ,t
)=
C
(
t
)
e
−
t
(3.7)
é
(3.7)
ü
à
'
u
t
¦
∂ω
m
(
θ,t
)
∂t
=
dC
(
t
)
dt
e
−
t
−
C
(
t
)
e
−
t
(3.8)
ò
(3.7)
“
\
(3.6)
2
éá
(3.8)
dC
(
t
)
dt
=
e
t
m
·
L
(0)
2
π
(3.9)
é
(3.9)
†
m
ü
>
È
©
C
(
t
)=
ω
m
(
θ,
0)+
m
·
L
(0)
2
π
e
t
−
1
(3.10)
ò
(3.10)
“
\
(3.7)
ω
m
(
θ,t
)=
ω
m
(
θ,
0)+
m
·
L
(0)
2
π
e
t
−
1
e
−
t
(3.11)
Ï
•
ω
m
(
θ,
0)=
m
·
L
(0)
2
π
,
¤
±
ω
m
(
θ,t
)=
m
·
L
(0)
2
π
,
=
½
n
1.2
¤
á
.
í
Ø
2
A
O
/
,
m
=2
ž
,
X
J
Ð
©
4
à
-
‚
´
°
Ý
ω
(
θ,
0)=
L
(0)
π
~
°
-
‚
,
@
o
3
6
(1.6)
e
u
Ð
,
-
‚
±~
°
,
¿
…
°
Ý
†
Ð
©
-
‚
°
Ý
ƒ
.
©
`
:
3
½
n
1.1
¥
,
e
m
=2,
K
T
(
J
3
©
[5]
¥
Š
Ÿ
p
ï
Ä
.
©
(
J
3
½
Â
2
Â
°
Ý
¼
ê
Ä
:
þ
é
ƒ
c
(
J
?
1
í
2
,
ƒ
é
u
ƒ
c
®
k
(
J
,
¬
•
´
L
˜
.
ë
•
©
z
[1]Gage,M.E.(1984)CurveShorteningMakesConvexCurvesCircular.
InventionesMathemati-
cae
,
76
,357-364.https://doi.org/10.1007/BF01388602
[2]Pan,S.L.(2001)OnaPerimeter-PreservingPlaneCurveFlow.
Applied Mathematics-AJournal
ofChineseUniversities
,
16
,409-417.https://doi.org/10.1007/s11766-001-0009-z
[3]Pan,S.L.andYang,J.N.(2008)OnaNon-LocalPerimeter-PreservingCurveEvolutionProb-
lemforConvexPlaneCurves.
ManuscriptaMathematica
,
127
,469-484.
https://doi.org/10.1007/s00229-008-0211-x
[4]Ma,L.andZhu,A.Q.(2012)OnaLengthPreservingCurveFlow.
Monatshefte f¨ur Mathematik
,
165
,57-78.https://doi.org/10.1007/s00605-011-0302-8
[5]
Š
Ÿ
p
.
²
¡
þ
˜
«
•
Ý
-
‚
6
[D]:[
a
¬
Æ
Ø
©
].
þ
°
:
u
À
“
‰
Œ
Æ
,2010.
[6]
À
(
,
‘
²
.
²
¡
þ
˜
a
1
w
à
-
‚
6
[J].
A^
ê
Æ
†
O
Ž
ê
ÆÆ
,2017,31(1):114-121.
[7]
r
•
²
,
‘
¹
ƒ
.
‡
©
A
Û
[M].
®
:
®
p
˜
Ñ
‡
,2008.
DOI:10.12677/pm.2023.13100879
n
Ø
ê
Æ
ë
¬
©
§
ÜL
[8]Ou,K.andPan,S.L.(2010)SomeRemarksaboutClosedConvexCurves.
PacificJournalof
Mathematics
,
248
,393-401.https://doi.org/10.2140/pjm.2010.248.393
DOI:10.12677/pm.2023.13100880
n
Ø
ê
Æ