Title
Author(s)
Citation
Issue Date
ON ENERGY INEQUALITIES OF MIXED PROBLEMS
FOR HYPERBOLIC EQUATIONS OF SECOND ORDER
Rentaro, AGEMI
Journal of the Faculty of Science, Hokkaido University. Ser. 1,
Mathematics = 北海道大学理学部紀要, 21(3-4): 221-236
1971
DOI
Doc URL
http://hdl.handle.net/2115/58108
Right
Type
bulletin (article)
Additional
Information
File
Information
JFS_HU_v21n3_4-221.pdf
Instructions for use
Hokkaido University Collection of Scholarly and Academic Papers : HUSCAP
ONENERGYINEQUALITIESOFMIXEDPROBLEMS
FORHYPERBOLICEQUATIONS
OFSECONDORDER
By
Rentaro AGEMI
~
1
. Introduction
Let R
/
' be t
h
e open h
a
l
fs
p
a
c
e {ヱ =(x' , x,,) ε l{n; x' ε Hη\ xn>O} and
Rt
"i
t
sc
l
o
s
u
r
e
. W ec
o
n
s
i
d
e
ra h
y
p
e
r
b
o
l
i
co
p
e
r
a
t
o
ri
n [0 , T]X R7~ (T>0
):
(
1
.1
)
2
。2
n .;:.,
a2
:.,
0
P(t, x;D)= ~,:;;- -2I
;a
j(t , x)-~~~--- I
; ajk(t, x) ー十一一
2
。t
; τ1 '"
蚯蛉j j ・ b1 '"
蛉j蛉k
+(
f
i
r
s
to
r
d
e
r
)
I•
which s
a
t
i
s
f
i
e
s
(件1. 司2)
主主1 {いいい向内川
Jμk(仇
川
μ
川
μ
ム
刈)川+ 向帆(仇川川ム
x
川
μ
羽) α向
x
叫kμJ
ω
川(伊仇
州
μ
(ムμ
川
t,, 刈xx)斗)} ~乙伏
ふ
J
i~kρ>0
j
(但1. 司3)
正仏
zムJ川z口?川
f
o
r any(υt, 二Z
羽
Eめ)ε[刊
0, T]X R7守~, and any non-z詑ero ~=(ぽ
~1 γ, ..一, ι)ε R/'匁£ヘ The c
o
n
d
i
ュ
t
i
o
n (但1. 勾2) me朗ans t
h
a
t P(t, x
;D) i
ss
t
r
i
c
t
l
yh
y
p
e
r
b
o
l
i
c and (
1
.3
)a
s
s
u
r
e
st
o
ne boundary condition on a mixed problem considered below (
c
f
.
impose o
~2
)
. Here weassume t
h
a
ta
j
k are symmetric. Moreover we consider the
t
):
f
o
l
l
o
w
i
n
gboundary o
p
e
r
a
t
o
r on t
h
e boundary [0 , T]x(R n, -R"
(
1
.4
)
~11_1 _L _j\ a
B(t, x';D)= :
:
.
V -I; bj(t, x') ~V_--c(t,
藕n ;
:
:
1
'" '藕j
x')
,
蚯
十ん (t,
x
'
).
Hereweassumet
h
a
ta
l
lcoe伍cients i
n(
1
.1
)and(
1
.4
)a
r
er
e
a
lvalued , su伍Cl
e
n
t
l
y smooth andc
o
n
s
t
a
n
te
x
c
e
p
ta compact s
e
t
.
In t
h
ec
a
s
eo
fo
p
e
r
a
t
o
r
s with c
o
n
s
t
a
n
t coe伍cients , a n
e
c
e
s
s
a
r
y and
su伍cient c
o
n
d
i
t
i
o
nf
o
rL
2
w
e
l
l
p
o
s
e
d
n
e
s
s1) o
f a mixedproblem with homo崎
1) T
hem
i
x
e
dp
r
o
b
l
e
m(P, βis L
2
w
e
l
l
p
o
s
e
di
fa
n
do
n
l
yi
ft
h
e
r
ee
x
i
s
tp
o
s
i
t
i
v
ec
o
n
ュ
s
t
a
n
t
sC, T a
n
d1" (
0
<1
"
:
:
:
:
;1
'
)s
a
t
i
s
f
y
i
n
gt
h
ef
o
l
l
o
w
i
n
gp
r
o
p
e
r
t
y
:F
o
re
v
e
r
yj ε H1((0 , T)
xR';)w
i
t
hf=O(t<0
)t
h
ep
r
o
b
l
e
m
PU=f(t>O , :J:: n>O) ,
Bu 二 o (t>O司工戸 0), u= 竺 =0 (t=O , :J::n>O)
h
a
sau
n
i
q
u
es
o
l
u
t
i
o
nuEH2((0,
οι
T')xR~')
1~'o|li 吋
s
u
c
ht
h
a
t
)I,!t ιcjOi 九 ):1μ
R
. Age/l1i
222
geneous i
n
i
t
i
a
l
b
o
u
n
d
a
r
yc
o
n
d
i
t
i
o
n
si
se
s
t
a
b
l
i
s
h
e
di
n[
1
](
s
e
ea
l
s
o[
1
0
]
)
. Let
P(t, x
;D)and B(t, x
'
;D)be t
h
ec
o
n
s
t
a
n
tcoe伍cient o
p
e
r
a
t
o
r
sr
e
s
u
l
t
i
n
g from
t(t , x
)
. Thent
h
i
sc
o
n
d
i
t
i
o
ni
sw
r
i
t
t
e
nbyt
h
et
e
r
m
s
f
r
e
e
z
i
n
gt
h
ecoe伍cients a
o
f coe伍cients、 that is ,
(
C1
)a
"
"(t, x)c(t, x
'
)+aη (t, x)~O and
h
ef
o
l
l
o
w
i
n
gq
u
a
d
r
a
t
i
c formH(t, x; σ) i
n σ=(σ1 , "', (Jn 択 Rn 1i
s
(
C2) t
p
o
s
i
t
i
v
e semi-definite,
where
H(作t, 川
x; σ
剖)
=(仇
仏仇7η叩
μ
z口ln川る C什十 αι
,,)2(何
a,ηz口lne
引
αη肌ηn o + b 戸
)2 ,
αn川n 十 a;l引)(切
一(何
α=
I
;aj(t, x) σj ,
b=I
;anj(t, x)aj ヲ
j 1
o= :E bj(t, x') σj
e
=
,
I; αjk (t, x) σ3σk ・
j.k~1
When a
"
"
c+a
">
0andH i
sp
o
s
i
t
i
v
ed
e
f
i
n
i
t
eont
h
eboundary , i
ti
ss
oc
a
l
l
e
d
t
h
eu
n
i
f
o
r
m
l
yL
o
p
a
t
i
n
s
k
i
ic
o
n
d
i
t
i
o
n
. These f
a
c
t
sa
r
eprovedi
n~ 2
.
The purpose o
ft
h
i
sp
a
p
e
ri
st
o prove t
h
ef
o
l
l
o
w
i
n
genergy i
n
e
q
u
a
l
i
t
y
which i
s shown i
n~ 3
.
Theorem. SU}ザose t
h
a
tt
h
ec
o
n
d
i
t
i
o
n
s (C1
)and(
C2) a
r
es
a
t
i
s
f
i
e
d on
t
h
e boundaゥ [0, T]x(R そ - R'~ .
) Then t
h
e
r
ee
x
i
s
t
sa ρositive c
o
n
s
t
a
n
tK
s
u
c
hthatfore
v
e
r
yr
e
a
luEH2((0 , T)xR"
t
)withBu=Oon[0 , T]x(R";-R":)
o
l
d
s
:forany t(0 三二 t 三三 T)
t
h
ef
o
l
l
o
w
i
n
ge
n
e
r
g
y inequali砂 h
(15)lu(t, )(|l 〉 K(jl(凸)(s , );|;hllu(o ,)|||:),
wl;げe Ilu( ・ )II~= Ilu( ・)1
1
~.' (
l
ln) a
nd
u(t , • )日
=1114(t , )||:+11 仇):
I
i+到?と (t)l:
I
tseems t
o us t
h
a
t one o
f di伍culities o
f ourproblemcomes from t
h
e
-=0 and σε Jln-l
f
o
l
l
o
w
i
n
gf
a
c
t
:t
h
e
r
ei
s non z
e
r
ov
e
c
t
o
r (τ, σ) with Rer
such t
h
a
tL
o
p
a
t
i
n
s
k
i
id
e
t
e
r
m
i
n
a
n
t R( -r, σ) =0 and t
h
ec
h
a
r
a
c
t
e
r
i
s
t
i
ce
q
u
a
t
i
o
n
P( -r, a, え)=0 h
a
s apureimaginaryd
o
u
b
l
er
o
o
twithr
e
s
p
e
c
tt
o;
f
)
. However,
we can a
v
o
i
dt
h
i
s di伍culity by i
n
t
r
o
d
u
c
i
n
gt
h
e above a
l
g
e
b
r
a
i
cc
o
n
d
i
t
i
o
n
s
(
C1
)and(
C2).
Combining t
h
e method o
ft
h
ep
r
o
o
fo
ft
h
e theorem with a c
e
r
t
a
i
n
remark, i
ti
s shown t
h
a
t energy i
n
e
q
u
a
l
i
t
i
e
so
fh
i
g
h
e
ro
r
d
e
ra
r
ev
a
l
i
d
. By
2)
S
e
e!
:
2a
n
dr
e
f
e
ra
l
s
ot
o[4] ,
[
7
]a
n
d[
8
]
.
I
np
a
r
t
i
c
u
l
a
rc
o
n
s
i
d
e
ro
n
l
yT w
i
t
hRe7" 孟 O.
OnEnergyI
n
e
q
l
l
a1
i
t
i
e
sof!o,1i:red P
r
o
b
l
e
l
l
l
sfìο rHyρ erbolic E
q
l
l
a
t
i
oJ1s0
/SecondOrdl'r 223
t
h
emethodo
fapproximation, we can show t
h
ee
x
i
s
t
e
n
c
e and t
h
er
e
g
u
r
a
l
i
t
y
o
ft
h
es
o
l
u
t
i
o
no
f ourproblem if
戸内止 (t, x)ç正k
i
sp
o
s
i
t
i
v
e de五nite.
Here
weu
s
et
h
ef
o
l
l
o
w
i
n
gf
a
c
t
s
: Cauchy-Kowalewskytheorem[
9
]withr
e
s
p
e
c
tt
o
mixed problem and t
h
a
tt
h
ec
o
n
d
i
t
i
o
n
s (C and (C
r
ei
n
v
a
r
i
a
n
tunder t
h
e
2) a
3.
Holmgren t
r
a
n
s
f
o
r
m
a
t
i
o
n
sl
2
]and[
3
]
.
Concerning a
l
r
e
a
d
yknown r
e
s
u
l
t
sr
e
l
a
t
e
dt
h
i
s problems s
e
e[
The author wishes t
oe
x
p
r
e
s
sh
i
ss
i
n
c
e
r
eg
r
a
t
i
t
u
d
et
oP
r
o
f
e
s
s
o
r T.
S
h
i
r
o
t
af
o
rh
i
si
n
v
a
l
u
a
b
l
es
u
g
g
e
s
t
i
o
n
s and c
o
n
s
t
a
n
t encouragement.
j)
Conditions(Cj) and(C
)
2
~2
.
I
nt
h
i
ss
e
c
t
i
o
n we show that, i
nt
h
ec
a
s
eo
fc
o
n
s
t
a
n
t coe伍cients , c
o
n
ュ
)a
r
ean
e
c
e
s
s
a
r
y and su伍cient c
o
n
d
i
t
i
o
nf
o
r V-wellュ
d
i
t
i
o
n
s(
Cj) and (C
2
r
e
p
o
s
e
d
n
e
s
s
. Throughout t
h
i
ss
e
c
t
i
o
n we assume t
h
a
t P(D) and B(D) a
o
t
a
t
i
o
n
si
n[
1
]
.
homogeneous andwith c
o
n
s
t
a
n
t coe伍cients. We use n
F
i
r
s
to
fa
l
ll
e
tus remarkt
h
a
tt
h
ec
o
n
d
i
t
i
o
n(
1
.2
)i
se
q
u
i
v
a
l
e
n
tt
h
a
t
(
2
.1
)
(
2
.2
)
where, α,
a肌十 a;,
> 0 and
t
h
eq
u
a
d
r
a
t
i
c form D(σ) = (α山 + a;,)(α2 +e) 一 (a nα +b )2
i
sp
o
s
i
t
i
v
e de五nite ,
band ea
r
e def ned
i
n~ 1
.
L
e
t P(" σ, ).)=,2-2iα, -2訂za
ι",).+α
仏,ι口",À
ynomla
心1 f
o
r P(D) and l
e
t.
)I(ケ"σ剖)(υ). (ケ"σ叫)) be a roo叫t i
n.
)o
f P(ケ" ).λ, σ
引)=0
whichh
a
sp
o
s
i
t
i
v
e(
n
e
g
a
t
i
v
e
)imaginaryp
a
r
tf
o
r, ε c = {,: Re, >O} r
e
s
p
e
c
t
ュ
1
.3
)theya
r
ew
r
i
t
t
e
nbyt
h
eformi
nC , :
i
v
e
l
y
. Thenby(
).ic(ケ', σ剖
a )=α仏?η」
中;
aJ
where t
h
es
q
u
a
r
e ro∞Ot()3iおs determined such 出
t ha此t Re ( )芦f>O i
H
fI
R
r
4
F
Moreover we c
o
n
s
i
d
e
r ).ic(" σ) t
obe c
o
n
t
i
n
u
o
u
s
l
y extended t
o C+x
Rη1 w
here C 十 is t
h
ec
l
o
s
u
r
eo
f C. By t
h
ec
h
o
i
c
eo
ft
h
es
q
u
a
r
er
o
o
ti
t
i
m
p
l
i
e
s
>
, >0.
(ロ2.3剖)
(置
I川 { }ρ
灼
J打川)川(ド(α仇nn+
口?
where t
h
eb
r
a
c
k
e
t {}吉 iおs t
h
e悶
s ame one i
n.
) (ケ"σ剖) .
Tog
e
ta n
e
c
e
s
s
a
r
y and su伍cient c
o
n
d
i
t
i
o
nf
o
r Lにwell-posedness , z
e
r
o
s
o
fL
o
p
a
t
i
n
s
k
i
id
e
t
e
r
m
i
n
a
n
t R(" σ) i
nC x[l" 1 and t
h
eb
e
h
a
v
i
o
ro
ft
h
e re同
f
l
e
c
t
i
o
n coe伍cient C(" σ) n
e
a
rz
e
r
o
sp
l
a
yan i
m
p
o
r
t
a
n
tr
o
l
e
. I
nt
h
i
s case,
:
l
) See t
h
e remark i
nt
h
e end o
ft
h
e paper
R
.Agemi
2
2
4
(
2
.4
)
R(r:, σ)
=i
)
.
i(r:,
=
σ)-ió-cr:
一正a}~}
ι
伝
五ム斗?
一2
丘i(何
a 肌n?勾"Q-
C(ケr:,川σド
a (ドd(日)-ió 一口} /
R( r:, a
)
Applying now t
h
er
e
s
u
l
t
si
n[
1
]t
ot
h
i
sc
a
s
e we o
b
t
a
i
nt
h
ef
o
l
l
o
w
i
n
g
w
e
l
l
p
o
s
e
d
n
e
s
s
.
c
r
i
t
e
r
i
af
o
rL2Theorem.
(
A
) l
ft
h
emixedproblem(P, B) i
s V-weZZ-posed, t
h
e
n5
(r
:
)= {σεBn1;
i
sind,φendent ofr: ε(\.
(
B
) Let5(r
:
)(
=
5
)beind,φendent of:
rE(! . Then t
h
emixedproblem
(P, B) i
s V・ wellアosed i
fand only グ the r
e
f
l
e
c
t
i
o
n coφ、cient C(r:, σ) i
s
r
o=O o
r(r:o , σ。)ε(!+ X 5
.
boundedi
na neighbourカood of(r:o , σ。)手 o withRe:
R(r:, σ)=O}
As a s
p
e
c
i
a
lc
a
s
eo
f(
B
) we s
e
et
h
a
t
B
)s
a
t
i
s
f
i
e
st
h
eu
n
i
f
o
r
m
l
y Lo.ρatinskii c
o
n
d
i
t
i
o
n(
t
h
a
t is, i
f
loranynonz
e
r
o (r:, σ)εC xRn-l) , t
h
e
nt
h
emixedproblem(P, B
)
(c)ザ (P,
R(r:, σ) ,* 0
i
sV-wellアosed.
Using t
h
e theoremwe s
h
a
l
l show t
h
a
tt
h
ec
o
n
d
i
t
i
o
n
s(
C1
)and (
C2) a
r
e
an
e
c
e
s
s
a
r
y and su伍cient c
o
n
d
i
t
i
o
n
sf
o
rV
w
e
l
l
p
o
s
e
d
n
e
s
s
. To prove t
h
i
s
we need t
h
ef
o
l
l
o
w
i
n
g lemmas.
.
Lemma2
.1
(
i
) lf LlnnC+ ι 手一 (a nn +a~J} , t
h
e
n R( r:, 0) 手 o i
n C 十一 {O} .
(
i
i
) l
fa
n
n
c+ ι= 一 (dMz+ai)J , then R(T, O)=O i
n f ト and C(r:, σ) i
sn
o
t
) (r:oε 0,).
boundedi
nanyneighbourhoodof(r: o, 0
Proof By the choise o
ft
h
e square r
o
o
tweg
e
t
R( r:, 0
)=-a;;,! {ω +an+(a nn + α討を} :
r,
C
(け )={a仏
九
ι
η附zυ叫肌P花ρ&
whichpr
oves t
h
e lemma.
H
e
r
e
a
f
t
e
r we mayassume thatσ 手 O.
Now i
tf
o
l
l
o
w
s from(
2
.
4
)t
h
a
t R(r:, σ)=0 i
m
p
l
i
e
s
(但2.5町)
F(ケM
刊,川
σ剖) = {(何a仏
ιιιμ
川肌4日?山 ημa
+(
a
n
n
c
+a
n
)
(
a
n
n + 同}r:ー (annó+by ー (a n "e-b 2 )=0 ,
where t
h
ef
フr
s
te
q
u
a
l
i
t
yi
s a de五nition.
OnEnergyl刀 equaliti,目。>/ MixedProblemsforH
y
p
e
r
b
o
l
i
cE
q
u
a
t
i
o
n
s01SecondOrder 225
Ther
o
o
t
si
n'
!o
f F(!', σ)=0 a問
(
2
.
6
)
-i{(仏mC + ι)(a側b 十 b) +'(annα -anb)} 土 (H(σ)- a'肌D(a))ま
(
a
n
n
C+a n )2 一(仇η +a~)
whereH(σ) i
st
h
eq
u
a
d
r
a
t
i
cf
o
r
m.i
n(
C
2
.
6
)i
ti
ss
e
e
nt
h
a
t R(勿, σ)
.
) From(
2
手o f
o
r any r
e
a
l ηif H(σ)-an"D(σ)>0 and R(!', σ) 手 o f
o
r any !
'
E0十 if
H(σ)-an"D(σ)<0.
Nowwe 五rst c
o
n
s
i
d
e
rt
h
ec
a
s
et
h
a
t(
a
"
"
c+a n )2 学 G肌 + a~ and i
n
v
e
s
t
i
g
a
t
e
z
e
r
o
so
fL
o
p
a
t
i
n
s
k
i
i determinanta
c
c
o
r
d
i
n
gt
oa s
i
g
no
fH (σ)-annD(σ).
Lemma2
.
2
. Supposet
h
a
t(a""c+ ι)2手 a n " +a~ andH(ao)-annD{ao)>O
forsome σ。手 O. Then
(
i
)
R(祢 σ) =
1
=0 forany real η ,
(ii)
ザ annc+a,, >O ,
R(!', σ。)手 o
(
i
i
i
)
i
fannc+a,, <O ,
R(!'o ,
forany!'EO+ ,
σ。)=0 f
orsome!
'
o
E
C
+
.
ReJηark 1
) Int
h
i
s lemmawemayassume t
h
a
ta
n
n
c+ ι 手 O. In fact ,
i
fa"nc+ ι=0, thenH(σ。)=ー (α肌 +a~)(aη点。+ b
)
2whereモo
=ó(σ。) andbo=b(σ。).
o
Henceby(1. 3), (
2
.
1
)and(
2
.
2
)wehaveH(σ。)-annD(ao)<O. Thisc
o
n
t
r
a
d
i
c
t
s
t
h
ea
s
s
u
m
p
t
i
o
n
.
2
) I
f annc+a,, <O andH(σ)-annD(σ) i
sp
o
s
i
t
i
v
e de五nite, then by t
h
e
p
r
o
o
fo
ft
h
i
s lemmaS
(
!
'
)depends on !'ECc ・
Proof ザ LeJnma 2
.2
. From t
h
eremarkmentionedb
e
f
o
r
et
h
i
s lemma
oprove (
i
i
)and(
i
i
i
)
. I
ti
so
b
v
i
o
u
st
h
a
t R(τ, σ。) =
1
=0 e
x
c
e
p
tr
o
o
t
s
i
t su伍cies t
e
t
!
'
obea r
o
o
to
fF(!', σ。) =O
. Then i
tf
o
l
l
o
w
s from
i
n'
!o
fF(!', σ。)=0. L
(
2
.
4
)(
2
.
5
)t
h
a
t
)
}
R(!'o , σ0) =-a~,~ [{(annC+ 仇ho+i(αnnÓO +b
o
+{{ド(aω
九,匁削肌
ι
仏
nn
九
日山
~nC
η〆
什
,cC叶+ αιω
川)
勾J
Byt
h
ec
h
o
i
c
eo
ft
h
es
q
u
a
r
er
o
o
twe o
b
t
a
i
n
1-2a~~~(annc 十 α"ho+i(annóo+bo)f
i
f annc+an>O ,
l
i
f a開c+an<O ,
R(!'o , σ。)={L
J
0
fromwhichoura
s
s
e
r
t
i
o
nf
o
l
l
o
w
sd
i
r
e
c
t
l
y
. Remark2
)i
sprovedbyt
h
eabove
e
q
u
a
l
i
t
yand(
2
.
6
)
.
Lemma2
.3
. Supposet
h
a
t(annc+ ι)2 手 ann+a;, andH(ao)-annD(σ。)豆 O
forsome σ。 =1= 0. Then
(i
) R(!', σ。)学 o forany 日 C"
R
.Agemi
2
2
6
(
i
i
) ザ H(σ。)>0 and annc 十仇 >0 , R(勾, σ。)手 o foranyreal η ,
(iii) ザ H(σ。)=0 and annc+ αよ 0 , R(旬。, σ。) =0 f
or somer
e
a
l1
)
0' b
u
t
)i
sboundedi
na ne留hbourhood of(句。, σ仏
C('r, a
(iv) ザ H(σ。)<0 o
ri
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n
n
c+an<
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h
e
r
ee
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i
s
t
sareal りo
s
u
c
ht
h
a
t R(旬。, σ。)=0 andC(!', σ) i
sn
o
tboundedi
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(勿0 , σ
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向
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nt
h
ec
a
s
e伊
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a ss叩
ume 出
t ha
叫t 仇
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仇n 守手丘 O
. I
nfact , i
f
annC+ ι=0 t
h
e
nby(
2
.
1
)wehaveH(σ。)=一 (ann + 吟) (
a
n
no
+bo)2 豆 O.
R仰仰zark
沈
kι.
ProofofLemma2
.3
. (
i
)i
sprovedb
e
f
o
r
eLe
mma2
.
2
. By (
2
.
6
)and
t
h
ea
s
s
u
m
p
t
i
o
no
ft
h
e lemma t
h
ee
q
u
a
t
i
o
n F(勿, σ。)=0 i
n ηhas two r
e
a
l
x
c
e
p
tr
o
o
t
si
n ηof
r
o
o
t
s(
c
o
u
n
t
i
n
gt
h
em
u
l
t
i
p
l
i
c
i
t
y
)
. C
l
e
a
r
l
y R(勾, σ。)学 o e
F(勾, σ。)=0. Let りo b
ear
o
o
to
f F(勿, ao). Theni
tf
o
l
l
o
w
s from (2.3) , (
2
.
4
)
and(
2
.
5
)t
h
a
t
(
2
.
7
)
R(句。, σ。)
I
-----,'"
2ia;~ ~ (~nC 十 a,,) η。 + a
n
n
モ+b
o
f
l
'
"
"
- "
'
/
" --,.,."
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J
i
f G(σ。)>0 ,
l
i
f
O
={
0
G(σ。):::;:0 ,
and
t
h
enumerator {
,~"
o
f C(旬。, σ。)
(
2
.
8
)
i
f G(σ。)ミ 0 ,
0
={~. ,(,
<
.
.
.
1
1-2iaム~ {(annc 十 a,,) 布。 +a""óo+bof i
f G(ao)>O
,
where α。 =α(σ。) andG(σ。)= {(annc+ ι)η。+ a
n
n
モ
}{
(
a
o
n
n+a;) η。 -(annoo-anbo)}.
O+b
Tod
e
t
e
r
m
i
n
eas
i
g
no
fG(σ。) wef
i
r
s
tremarkt
h
ef
o
l
l
o
w
i
n
gf
a
c
t
s
. Subュ
)
f
(
a
n
n
c+an
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;
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sv
a
l
u
e
so
f!' i
n
t
o
s
t
i
t
u
t
i
n
g -i(αnnÓ +b
F(!', σ) weg
e
td
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l
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l
l
o
w
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n
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e
l
a
t
i
o
n
s
:
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F
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a)
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向
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,帥d
w,HC(帥
(
2
.
9
)
F
(annα-dt.ρ= 一五 nD(a) -_!_回2
)
2,
1am+aiz-jam+G2(α "n +a;
wh町e I(σ)=(annC+ ι)(a"no-anb ) + 仲間 +a;)(a"n ó + b )ー
Hencei
tf
o
l
l
o
w
sfrom
(
1
.3), (
2
.
1
)and(
2
.
2
)t
h
a
t
(
2
.
1
0
)
~oreover
F
(a"nO 二坐 t, σ) is 時ative
¥ an匁 +a匁/
d
e
f
i
n
i
t
e
.
byt
h
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o
l
l
o
w
i
n
gr
e
l
a
t
i
o
n
s
:
(
2
.
1
1
)
anno-a"b
a畑 +a;
/ ann +b¥_
1(σ)
c+a ,,)
¥ a"nc+an) (
a
"
n+a
;
)
(
a
"
n
一一一
-
,
OnEnergyInequaliti,目
(
2
.
1
2
)
of
MixedProblemsforHypelるo/ic E
q
u
a
t
i
o
n
sofS
e
c
o
l
l
dOrder 2
2
7
一 (ann C+ ι)(α開ó+b) 一 (a肌α -anb)
¥
(α肌ó+b
(
a
n
"
c+a n J2 一 (an " +a
;
)
¥ annc 十 anJ
-I(σ)
(α問 c+ α,,){(α附c+ αJ ー (a"n +a
;
)
},
wheret
h
ef
i
r
s
ttermo
ft
h
el
e
f
thando
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2
.1
2
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sav
a
l
u
ea
twhicht
h
ef
u
n
c
ュ
t
i
o
nF(勿, σ) in り take anextremum.
n
"
c+ ι>(anJd)E , because f
o
ra
n
o
t
h
e
r
Wec
o
n
s
i
d
e
ro
n
l
yt
h
ec
a
s
et
h
a
ta
c
a
s
e (iiト(iv) a回 proved by t
h
e same method. 1
nt
h
i
s c
a
s
e F(勿, σ) i
sa
c
o
n
c
a
v
ef
u
n
c
t
i
o
ni
nη.
、。一
24a 一品
'hu-
G
一一+一一+
向一四%一肌
a一
a一間一
間一
G一
<>
z
一α
ddpM
一
均一弘弘一
h
h
一一
G 一 aa
り仇
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This showst
h
a
t G(σ。)>0.
け一'引h
け一
(
i
i
) Thec
a
s
et
h
a
tH(uo)>O. 1
tf
o
l
l
o
w
sfrom(2.9)一(2.12) t
h
a
tI(σ。)*0,
i
f
I(σ。)>0 ,
i
f
I(σ。)<0.
Henceby(
2
.
6
)wehaveR(旬。, σ。)手 O.
(
i
i
i
) Thec
a
s
et
h
a
tH(σ。)=0. By (
2
.
9
) we s
e
e thatη。=一 (a開ó o + b
o
)
f
i
sar
o
o
tin り of F(勿, σ。) =O
. Hencebyt
h
esamea
st
h
ec
a
s
e(
i
i
)
R(iη, σ。)手 o f
o
rany ザヲ匂o. From(
2
.
7
)and(
2
.
8
)i
ti
se
a
s
i
l
ys
e
e
nt
h
a
tR(句。, σ)
=0andt
h
enumeratoro
f C(句。, σ。) i
se
q
u
a
lt
oz
e
r
o
. Top
r
o
v
et
h
a
t C('Z', σ)
i
s bounded i
n a neighbourhood o
f (旬。, σ。) we c
o
n
s
i
d
e
rt
h
ee
x
p
a
n
s
i
o
no
f
i
1
:
!
:('Z', σ) n
e
a
r(旬。, σ。). (
c
f
.[
6
]
)
. L
e
t P(τ, σ, i1)=('Z'-i-r 1 (σ, i1))('Z'-i-r2 (σ,i1)) where
'Z'j(σ,i1) (
j=1
.2
)a
r
er
e
a
la
n
a
l
y
t
i
candd
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s
t
i
n
c
tandmoreoverl
e
t1
i
0bear
o
o
t
io
f P(句。, σ。,え) =O
. Thenw
i
t
h
o
u
tr
e
s
t
r
i
c
t
i
o
nwemayassemet
h
a
t7
}
0
=
i
n1
(α同c+ ι)
'Z'1(σ0 , i
(
0
)andん= -(a,,7}o+ b
o
)
f
a
"
n
.
S
i
n
c
e1
i
0i
s double , wehave
空豆 (σ0 , i
(
0
)
=0
1
i
and~与(σ0 , 1
i
)*O. Hence t
h
e
r
ee
x
i
s
t
sar
e
a
la
n
a
l
y
t
i
cf
u
n
c
t
i
o
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o
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i
t
h
a
t i1川)=i10
and 竺l_ (u, ん(σ)) =0 i
nas
m
a
l
lneighbourhoodo
fUo ・ Now
。え
l
e
t
u
ss
e
t
l'Z' 一 η。= 'Z'1(σ, i1)-'Z'I(σ0 ,え。)
(
, 1 ,\
,,
1
哨
('1'\/'
'1'¥
='Z'I(σ,ん
(σ)) -'Z'I(σ0
, i(0) 十一
(σ))(
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i
0
(σ)r +・
¥
-,. /
., . ,
2 -1(σ,ぇ。
. -, .
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u
Le
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h
es
q
u
a
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o
o
tof
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ith posi・
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U
I
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U
t
i
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e
g
a
t
i
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e
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m
a
g
i
n
a
r
yp
a
r
tr
e
s
p
e
c
t
i
v
e
l
y
. Then f
o
ranarbitrarily
nearσo weo
b
t
a
i
nt
h
ee
x
p
a
n
s
i
o
ni
n~:!: o
f i1:!:('Z', σ) n
e
a
r旬。:
五xedσ
R
.Agemi
2
2
8
タ
:
f
:('r,
where Cj(σ) a児 real.
σ)
=À(σ)+e土十 C2 (σ)(e土 )2+ ・
Us
i
n
gん
À o(何
ωo)=À
向
σ
ん0= 一(悼
α
2り)
一 e++o((ぽぱ
Eι;)門
C('r, σ。)ー
e
-+0@-)
2
)
S
i
n
c
e W/~-I =1 and e(~-)→ o when 'r• i1)o, c(ケ'r, σ司) i
s bounded i
na
neighbourhoodo
f(収i守仇o , σ向
ω0)
(i討V
吋同
) The悶
c as問
et出
ha
叫tH(伊
ω心
向
σ
0)<0. Fro
ひ m(ρ2.ρ9
別)and (ρ2.10
的)we
“se
白
et出
ha
叫t t
h
e
r
e偲
e Xlおst岱
s
a ro∞O叫tη仇o between(α
仇ηnnα
向o 一 G
仇n点
凶
bO0心
0川
)//(αιn加η+α
a~) and 一 (annÓ o +b
o
)
/
(
a
n
n
c+a ",.). Hence
we havet
h
a
t G(σ。) <O
. C
o
n
s
e
q
u
e
n
t
l
yi
tf
o
l
l
o
w
s from (
2
.
7
)and(
2
.
8
)t
h
a
t
t
h
ec
o
n
c
l
u
s
i
o
no
f(
i
v
)i
nt
h
elemmai
sv
a
l
i
d
.
a
n
n
c+an
)
2=an
"+a~. I
nt
h
ec
a
s
et
h
a
t
Next¥
we c
o
n
s
i
d
e
rt
h
ec
a
s
et
h
a
t(
annC+a
s
eo
n
l
yLe
mma 2
.1f
o
ro
u
ra
i
m
.
n=-(a
n
n+ α~)吉 we u
Lemma2
.
4
. SψÞjJose t
h
a
ta
"
n
C+an=(a,日, +a n )き . Then
(i)ザ (annC+ ι)(α肌Óo +b
n
b
)
=0forsome σ。 *0, R('r, σ。)*0
)
+(a nnα。 - a
o
o
i
nC 汁
(
i
i
) i
f(annc+ ι) (anno+bo
+(annα。 -a"b件 o forsome σ。 *0, R('r, σ) 学 O
)
i
n0+andt
h
ec
o
n
c
l
u
s
i
o
n
sof(ii) , (必), (倒的 Lemma (
2
.
3
)a
r
ev
a
l
i
da
c
c
o
r
d
i
n
g
ω H(σ。)>0, H(σ。)=0, H(σ。)<0 re,ゆ ectively.
Proof We prove o
n
l
y(
i
)b
e
c
a
u
s
e(
i
i
)i
s proved by same method i
n
Lemma2
.
3
. I
nt
h
ec
a
s
e(iり) F(什'r, σ的
ω
o)=a
ι?η帥
z
f
o
l
l
o
w
si
m
m
e
d
i
a
t
e
l
yfrom(
1
.司3), (
2
.
1
)and(
2
.
2
)
.
Using Theorem (A), (B), (
C
) and lemmas (2.1)一(2.4) we can show t
h
e
f
o
l
l
o
w
i
n
g
Theorem2
.5
. Themixedproblem(P, B
)i
sV-ωell-posed ザ and o
n
l
y
i
fannc+ α之 o andthequadraticformH(σ) i
sρositive semi-de兵nite.
Proof 1
. Su伍ciency o
f our c
o
n
d
i
t
i
o
n
. F
i
r
s
tc
o
s
i
d
e
rt
h
ec
a
s
et
h
a
t
annC+ ι>0 a
nd H(σ)-annD(σ) i
sp
o
s
i
t
i
v
ed
e
f
i
n
i
t
e
. By t
h
e remark 1 o
f
Le
mma2
.2 wemayassumet
h
a
t a,〆 +ι>0. Note t
h
a
t H(σ) i
sp
o
s
i
t
i
v
e
di五nite a
nd(α帥c+an?*a間十 a~. I
nfact , t
h
ef
i
r
s
ta
s
s
e
r
t
i
o
nf
o
l
l
o
w
simmediュ
a
t
e
l
y from (
1
.3
) and (
2
.
2
)
. I
f (annC+an)2=ann+a~ , then H(σ)-annD(σ)=
ー {(annC+a n )(αnnÓ +b
)+(a nnα -anbW 豆 O. Hencei
tf
o
l
l
o
w
sfromLemma2.1 ,
2
.
2 and Theorem(
C
)t
h
a
tt
h
emixedproblem (P, B) s
a
t
i
s
f
i
e
st
h
eu
n
i
f
o
r
m
l
y
L
o
p
a
t
i
n
s
k
i
ic
o
n
d
i
t
i
o
n and c
o
n
s
e
q
u
e
n
t
l
yi
ti
sV
w
e
l
l
p
o
s
e
d
. Next c
o
n
s
i
d
e
r
t
h
ec
a
s
et
h
a
ta
n
n
c+ ι 二三 o andH(ao)-annD(σ。)豆 o f
o
rsomeσ0 ・ I
f H(σ。) i
s
h
e
nbylemmas 2
.
1
2
.
4t
h
eproblem (P, B)
a
l
w
a
y
sp
o
s
i
t
i
v
ef
o
rsucha
l
lσ。, t
s
a
t
i
s
f
i
e
st
h
eu
n
i
f
o
r
m
l
yL
o
p
a
t
i
n
s
k
i
ic
o
n
d
i
t
i
o
n
. I
fH (σ。) i
snonn
e
g
a
t
i
v
ef
o
r
s
u
c
ha
l
lσo andi
nf
a
c
t H(σ。)=0 f
o
rsome ao, t
h
e
nby lemmas2
.
1
2
.
4 S('
r
)
OnEnergyIn叩talities ofl
¥
1
i
x
e
dProblemsforH
y
p
e
r
b
o
l
i
cE
q
u
a
t
i
o
n
sofSecondOrder 2
2
9
=
c f
o
ranyT εC ト and t
h
er
e
f
l
e
c
t
i
o
ncoe伍cient C(Tσ) i
sboundedi
nan
e
i
g
h
ュ
bourhood o
f az
e
r
oo
fL
o
p
a
t
i
n
s
k
i
id
e
t
e
r
m
i
n
a
n
t
. Therefore t
h
e problem i
s
V乙-well-posed b
yTheorem B
.
2
. N
e
c
e
s
s
i
t
yo
f ourc
o
n
d
i
t
i
o
n
. F
i
r
s
t百
i fα
仇n口
mC
thenby lemmas 2.3 , 2
.
4andTheorem(
B
)theproblemi
sn
o
t Vュ
w
e
l
l
p
o
s
e
d
. Secondly i
f annc 十 an<O, αnnC+an 学 (α"n +a;,) and H(σ)-a肌D(σ)
i
sp
o
s
i
t
i
v
e defìnite, then by t
h
e remark2 o
f lemma 2
.
2 and Theorem(
A
)
t
h
eproblemi
sn
o
tV
w
e
l
l
p
o
s
e
d
. Thirdlyi
fa肌c+an<O, a"nC 十仇学仲間 +a~)
andH(σ。)-annD(σ。)豆 o f
o
r someσ。手 0, then by Lemma 2
.
3andTheorem
(
B
)t
h
eproblem i
sn
o
tV
w
e
l
l
p
o
s
e
d
. F
i
n
a
l
l
yi
f annc 十 a n = -(
an
n+a;,), then
.1andTheorem(
B
)t
h
eproblemi
sn
o
tD-well幽posed. Inafn
a
l
byLemma2
c
a
s
en
o
t
et
h
a
tS(T)={
O
}
. Thus theproof i
sc
o
m
p
l
e
t
e
.
s叩
omeσ
向0 ,
Remark. Fromt
h
ep
r
o
o
fo
ft
h
etheoremwes
e
et
h
a
t(P, B
)s
a
t
i
s
fe
st
h
e
sp
o
s
i
t
i
v
e
u
n
i
f
o
r
m
l
yL
o
p
a
t
i
n
s
k
i
ic
o
n
d
i
t
i
o
ni
fando
n
l
yi
fa,山C 十 an>O andH(σ) i
de五 nite.
~
3
. Energy i
n
e
q
u
a
l
i
t
i
e
s
.
I
nt
h
i
ss
e
c
t
i
o
nweproveTheorem s
t
a
t
e
di
n~ 1
F
i
r
s
to
fa
l
lwe may assume t
h
a
t B(t, x
'
:D) i
s homogeneous. I
n fact ,
wet
a
k
ear
e
a
lv
a
l
u
e
df
u
n
c
t
i
o
n cþ εC;;o ([O , T]xR空) withf
o
l
l
o
w
i
n
gp
r
o
p
e
r
t
i
e
s
:
J くゆく 1
c= 1 and
i
n [0 , T]xR~ ,
_aι 十ん= 0 on [0, T]x(R~ -Rて) ,
oX
n
and s
e
t u=cv
. Then u satis五es
~17
蛆
ov on [0
rA " " . I D
, T]x(R" - R
".
B(t, x
'
:D)u= 一一 -'L. br'::V -c 一一
axπ;-:1
-a
X
j
a
t
Hence i
tf
o
l
l
o
w
s fromt
h
i
s and i
n
v
a
r
i
a
n
c
eo
fp
r
i
n
c
i
p
a
lp
a
r
tt
h
a
tt
h
e energy
i
n
e
q
u
a
l
i
t
yf
o
ruf
o
l
l
o
w
s fromt
h
a
tf
o
rv
.
Denotet
h
ei
n
n
e
rp
r
o
d
u
c
t
si
nV(R'nandV(R:
n-Rて) by(・, .
)and く. ,
r
e
s
p
e
c
t
i
v
e
l
y
. Furthermore s
e
t IluI1 2 =(u, u
) and ((U))2= くu, u
)
. H
e
r
e
a
f
t
e
r we
'
:
) with B(t,: x
'D)u=O on t
h
eboundary
mayassume t
h
a
t u εC;;o ([O, T]xR
[0 , T]x(R竺 -R~).
Using t
h
ei
n
t
e
g
r
a
t
i
o
nbyp
a
r
t
s we o
b
t
a
i
nt
h
a
tf
o
rany t(O<t<T)
>
-
(
3
.1)
引川, .),かう
2
3
0
R
.11gemi
rau ,
,r; 2.
;::, /
,
au
,
au"
¥
=(iJr)|!?1 作品川 (s, .),ん (s'.))J 1 。
0) すs,
+2):<an(s,.,
• , 0)
+皇内仇, o)?:JM , o) ,
7s,, o)>d5+(fown-o物的l) ラ
(
3
.2
)
2
)
:(仇)同
)ι 仇い
ニ 2(学 (s, • )一志向 (s, )fu(s,), fι (s, • )
)I
¥dt
dXj
j 1
+2):<山,
o)7s,, o)+ 主 anj 仇, o)?: 同, 0) ,
手-(s,., O)>ゐ +(lωer
ordert
e
r
m
)
OX
k
(
3
.
3
)
!
1
0
dX
k
(ん =l , 2,, n-1) ,
引仇)(s,), Ci- 同い
=2(苧 (s, • )
¥dt
t r"au ,
+J
¥
<':~
(s,
o~l
at"
かj (s, ・)手竺 (s, ・), ~竺 (s,
dXj
j--l
~,,, ?
・, 0);}2+
dX
n
~, au
. 'ax ,,"
•)
¥
I
!
0
1
<ann(s,., 0
) ::O<_ (s,
....,.
・, 0) ,一一 (s, ・, 0)>
,. aX
n
-2< 竺 (s, • , 0) 上IGj(s,, O) 子竺 (s,., O)>
dt
dXj
j~l
-JZ1<川, 0) と同, 0) ,ーと仇, 0) >い
+(lowerorderterm).
n
t
e
g
r
a
lo
ff
o
l
l
o
w
i
n
gt
y
p
e
:
Here “ lower orderterm" means an i
):θu
au whose coe伍cients a
(
ab
i
l
i
n
e
a
rform i
n u , ー, ~~
r
ea
t
a
t
' aヱ3
most 五rst
d
e
r
i
v
a
t
i
v
e
so
ft
h
o
s
eo
fP andB
)d
s.
Consider t
h
ef
o
l
l
o
w
i
n
gi
n
t
e
g
r
a
l
:
(
3
.4
)
2('((Pu)(5,),
A(s, )h)+
む (s, • )手
(s,.•)
'
)
d
s,
J
0 ¥'
. a
t
j 1 "..
aX
j.
'
)
~
whereA(t, x
) and Aj(t, x
)a
r
er
e
a
lv
a
l
u
e
d and d
e
t
e
r
m
i
n
e
dl
a
t
e
ro
n
.
By t
h
e same c
a
l
c
u
l
a
t
i
o
na
s (3.1) , (
3
.
2
) and (
3
.
3
)t
h
ep
a
r
t (.,.)日 of t
h
e
i
n
t
e
g
r
a
l(
3
.
4
)becomes
OnEnergyI
n
e
q
u
a
l
i
t
i
e
sofl
'
v
f
i
x
e
dProblemsforH
y
p
e
r
b
o
l
i
cE
q
u
a
t
i
o
n
sofSecondOrder 2
3
1
)1
~:ペ) +
2
(~:η)'
J
(
3
.5
) [
(
A
(s , .
.)一
~:t(S, .,.))'
L
:A-j 仇)ー何
(
A(s
)曻t(s,.),
, . ,. 曻
J+2(一肌),
¥曻t, . ,. j
=
,. , 曻
Xj, .
+土 (
~凶凶
A(仇ム介川.→)同
α向川
j卯μk
ム.k~1川\、
j
,
d
X
j
dX
k
/J
I
Using t
h
er
e
l
a
t
i
o
n (Bu)(t , X' , 0)=0 and d
e
n
o
t
i
n
g f lx,, ~o=f(t, x' , 0
)t
h
e
boundaryp
a
r
to
ft
h
ei
n
t
e
g
r
a
l(
3
.
4
)becomes
<~2(annc 十 an)A 十 (ann C 2 + 1)Anf 一一!
i
j;i218uL
机
曻tI
x
_
.
o
'一一
曻t
.
.
.
.
,
Ix_~o
"J
>ds
A
・
4
d
n
G
d
qd
η
pι
'
o
G
,,
十
A
n
G'S
3
+6
'
oz n u
町一一
an
oj
>
B
以
vA
,、
d
<c
gOM
++
J汁
伽一白川
¥ ' •.•.
却と
(
3
.
6
)
、 rla,
l
+~日
t;;
宇玄1, <{い仰引均仇(何
aωη
肌ηnbj+切叫
G叫仇向川
刈nn j)A
ん加川
k汁川十叫(ι
川ηJ
ω
九
あ
nιυ
帆
叫
bþ
j片bι
い£
ム
Jo
ν
J.IL
凡
空竺
u.んj
Iη
>ds.
曻xk IXnco
F
i
r
s
t we s
e
et
h
a
tt
h
eq
u
a
d
r
a
t
i
c formc
o
r
r
e
s
p
o
n
d
i
n
gt
o(
3
.
5
)i
sp
o
s
i
t
i
v
e
de五nite
i
f and o
n
l
yi
f A>O and
n
o
n
z
e
r
o~ε Rn.
Put ち =
L
:(A2ajk-2ajAkA-AjAk)~j~k>0
L
:Aj(t, x) σj
where ~=(σ, ι).
f
o
rany
Then by r
e
w
r
i
t
i
n
g
t
h
i
sc
o
n
d
i
t
i
o
n weg
e
t
(
3
.
7
)
A
(
3
.
8
)
>0 ,
a nn N-2a n AAη -A~>O ,
(
3
.
9
)
t
h
ef
o
l
l
o
w
i
n
gq
u
a
d
r
a
t
i
cformL(t, X: σ) inσis p
o
s
i
t
i
v
edefinite,
where
L(μ;σ)
=(何G刷
一(何
仇?勾m
α
るη +a~) 芝ちラ2 十 2(拘
b十α
仇η点α
叫
刈)An芝~ 一 (似
α2 十 E的)A~し,
and α, b, bandea
r
ed
e
f
i
n
e
di
n~ 1
.
Nextwe s
e
et
h
a
tt
h
eq
u
a
d
r
a
t
i
c formc
o
r
r
e
s
p
o
n
d
i
n
gt
o(
3
.
6
)i
sp
o
s
i
t
i
v
e
semi-de負nite i
fando
n
l
yi
f ont
h
eboundary
(
3
.1
0
)
(
3
.1
1
)
2
2(annc 十 ι )A +(
a
c
+1)A n 孟
n
n
0 ,
t
h
ef
o
l
l
o
w
i
n
gq
u
a
d
r
a
t
i
cform J(ムど ;σ)
definite ,
inσis
n
e
g
a
t
i
v
es
e
m
i
ュ
2
3
2
R
. Age/lli
where
J(伊μ
, x'勺; σ判) ニベ{(何a nn
b2 一付 十 2A ηm
ahybv2
8
Gι附
n)
,))(μ仇肌
ιηnn〆CC+ α
仏仇叫川
刈,)川
n))(α仇n削nn削点
a〆c+a
C 川
偽
一(何dannc
ω
nn
n〆
mn cb α叫)
ι刈
ω川
判{(何九
利
一 (何
仇ηn九n C2
G
M
u
l
t
i
p
l
y
i
n
g J(伊t, X
i
v
e
s
i
m
p
l
ec
a
l
c
u
l
a
t
i
o
ng
'
;σ引) by (μG匁肌n〆c +an)
2as
(β3 悶
αι
(何
z口?ηz 問戸
九'"問
〆
)(a肌ぬ一 α叫)ト一(何
αι
,Cc+a
仏仇
αι
十{ (ほ
川,,)刈,)川
ω削肌
九
九
n川nn肌ηz C2
nnn
ω
+ Aπ ヤ (
a
n
n
c
+ι )A+(a
九
ι
n削nn肌 C2
)22可(何
n)2
c +a
G 削肌
C 仰肌
一(何ω
G仇九凡
μ?η
匁町削
ρ
〆
, C什
G仇削肌
九〆
,ι
什
川川ル
仇叫
匁
穴
nnカb022 一 e引)一(何ω
nn
nn b + 町)
ω
C
o
n
s
i
d
e
rt
nt
h
er
i
g
h
t hando
f(
3
.
1
2
)
. Comュ
h
el
a
s
tf
a
c
t
o
ro
f second term i
p
a
r
e coe伍 cients o
h
i
sf
h
o
s
eo
f H(σ). Then
f powers i
nco
ft
a
c
t
o
r with t
we s
h
a
tt
h
i
sf
a
c
t
o
ri
se
q
u
a
lt
e
et
oH(σ )/a nn . Consequently
(β3 悶
b削)
a川)戸悶
J
σ引) = [(何G仇九向川削間
叶州
〆
c 仇刈
C什+ ω
仇n)2~
α
刈 ト一 (何αι
叫
a刈)(何
n)川 αn間n点Q+
九引
(何Gι
訓ん州(ゆ刷
ω帥
九
nn
n c+a
n )22リ引
nn川
nn c + ι
η間n cb
μ
Jηc+α
間
n) αι
+{(何Gι
仇叫州
九
九
刈)(何
b糾)
α叫)-(何
Gι匁nn〆C2 叫
叫州
+ l抑 nn匁 b+
ω
九
叫}A
η, nr
九吋
AπH( σ) ~2(annc+
, l
,/~
(0/~ ~,,,
~22
!
I+
1¥
In
l
)A
(
a
c
)!
A
ι¥
n
n
+
f
a ,問、
J
e
tu
e
t
Now l
ss
A = (annc+ α n)2
(
3
.
1
4
)
ι (annc+ ι )+a nn 十 a~ ,
α n日"þ
Aj= 叫
Aη =-a 1バ α 肌 C 十 a ,ι)
(j=I ,… , n-1) ,
,
'
)(
Herewee
x
t
e
n
dt
h
ef
u
n
c
t
i
o
n
s c(t, x
'
)andbj(t, x
e
.fnedon
j= 1,… , n-1) d
'
)andbj(t, x)= ん (t, x
t
h
eboundaryt
o[0 , T]xRて as f
o
l
l
o
w
s
: c(t, x)=c(t, x
'
)
.
Thenwe s
h
a
l
l show t
h
a
tc
o
n
d
i
t
i
o
n
s(
3
.
7
)and(
3
.
8
)h
o
l
di
n [0 , T]xRn and
h
eboundary [0 , T]x(R マ -R,,+).
c
o
n
d
i
t
i
o
n
s (3.9) , (
3
.
1
0
) and(
3
.
1
1
)h
o
l
d on t
F
i
r
s
tby (C 1) , (
3
)
a
n
d
(
2
.
1
)
t
h
a
t
r
e
l
a
t
i
o
n
s
we s
e
e
1
.
A = (a~nc2 +a ",,aη c+a~)+ α nn ,
a
n
.
l
l
n
A-A;,
annA2- 2
)
4+(
a
a
n
n
C
+a ,,)2 (a nn +a;,) +(
=an
(
a
n
n
C
+an
n
n+a;,)2} ,
n{
OnEneγgy
Ine明alities
o
fmi工ed
Pγohlems
f
o
rHyperもolic E
q
u
a
t
i
o
n
so
fS
e
c
o
n
d0γdeγ
2
3
3
(
3
.1
5
) 2(a
仇叩
ω
d九ηC十 α
仇n)A+(何M
α仇削肌
dJ?η
九〆
zJCd2斗
2刊
+ 1川 n=(annC+ι )
(
(
ιρ
implyt
h
ea
s
s
e
r
t
i
o
n
s on (3.7) , (
3
.
8
) and (
3
.
1
0
)
.
Next , a
f
t
e
ral
i
t
t
l
ec
o
m
p
l
i
c
a
t
e
dculculation , we a
r
r
a
n
g
e L(σ) with r
e
s
p
e
c
tt
o
n
n
c+an. Thuswe s
e
et
h
a
t
powers i
na
(
3
.1
6
)
L(σ) =(annc+ 仇)官(σ)+annD(州annC+a n ? 十 (a nn +a;J} ,
whereD(σ)( =D(t, x; σ)) i
sd
e
f
i
n
e
dby(
2
.
2
)
. By(C 2), (
1
.3), (
2
.
1
)and(
2
.
2
)t
h
e
c
o
n
d
i
t
i
o
n(
3
.
9
)h
o
l
d
s on t
h
eboundary. F
i
n
a
l
l
y by a s
h
o
r
tc
a
l
c
u
l
a
t
i
o
nt
h
e
p
a
r
t[]o
f(
3
.
1
3
)v
a
n
i
s
h
e
s
. Hencei
tf
o
l
l
o
w
sfrom(
3
.
1
3
)and(
3
.
1
5
)t
h
a
t
J(σ)=-H(同 {(a",什仇)2 +(αJ
(
3
.
1
7
)
Consequentlyby (
1
.3
)and(C
)t
h
ec
o
n
d
i
t
i
o
n(
3
.
1
1
)h
o
l
d
s on t
h
eboundary.
2
Suppose t
h
a
tt
h
eq
u
a
d
r
a
t
i
c formL(t, x; σ) i
sp
o
s
i
t
i
v
e de凸nite i
n [0 , T]
xR ,,; .4) Then we s
h
a
l
l show t
h
e energy i
n
e
q
u
a
l
i
t
y(
1
.5
)
. The f
o
r
e
g
o
i
n
g
0<t~ T)
c
o
n
s
i
d
e
r
a
t
i
o
ng
i
v
e
st
h
a
tf
o
rany t(
/I u(~ , !2η òu (~ , 2\ T7'(
(
3
.1
8
)K
d
~~-(ム・) +L
;i:
_
:
u(t ,'); ¥-K(r
U│tl
三三 1
1
j ニ 1|lazj
f
t
(1 T l ¥ I
,
A I
メU ( A
'
2 ;
:
" メU I A
V
_
_ (0 , ・ ),+L:
~~-(O,・)
u
lf\lat
¥
,.), A(s, ・)
J((Pu)(s
, "
"
'"
¥
0 ¥'
メU I
V
_
_
u (s , ・)
t'
"
j110zj/
i
i¥
:,
メU
+L
:Aj(s, ・ )--:'.Ç
""-(s, .
))
d
s
'メXj'"
j
!
I
j ニi
I
¥
I
¥¥
J '
+J(lowerorderterm)I,
where A and Aj a
r
ed
e
f
i
n
e
d by (
3
.
1
4
) and c
o
n
s
t
a
n
t
s KI and K; a
r
ei
n
ュ
dependent o
fu
. Note t
h
a
t
(
3
.
1
9
)
(同 (s,'
)
n
r
:~叩パ
)|lLjJZ(s, );2) ホ
Using Schwarz i
n
e
q
u
a
l
i
t
yi
tf
o
l
l
o
w
s from (
3
.
1
8
) and (
3
.
1
9
)t
h
a
tf
o
rany t
ju(t, )i|: 叫 GIllu(s, )|17t+jJ|(h)(s, )|2ゐ+ 1
:u(0 , .
)
1
[
1
:
)
S
i
n
c
e S:II(Pu)(s , .)Wds+:ilu(O ,.
・
u
ιl
4
lagf'''J
一、、
、、
μ
ハυ
+
dcd
c
d
,島内
u
p
VA
pt・-E ,,d
'ji--J、I--1
E
K
9H'i
<=
4'b
u
(
3
.2
0
)
i
si
n
c
r
S
e
t K=K2e A ,T. Then(
3
.
2
0
)l
e
a
d
simmediatelyt
ot
h
eenergyi
n
e
q
u
a
l
i
t
y(
1
.5
)
.
3
.
1
6
)
Now we s
h
a
l
l remove t
h
e above a
s
s
u
m
p
t
i
o
n
. Note t
h
a
t by (
L(t, x; σ) i
sp
o
s
i
t
i
v
ed
i
f
i
n
i
t
e on t
h
eboundary. Then by t
h
eassumptionand
4)
T
h
i
sa
s
s
u
m
p
t
i
o
nmayb
er
e
m
o
v
e
da
f
t
e
r
.
R
.Agemi
234
c
o
n
t
i
n
u
i
t
yo
f coe伍cients t
h
e
r
ee
x
i
s
t
s as
m
a
l
lp
o
s
i
t
i
v
ec
o
n
s
t
a
n
t0s
u
c
ht
h
a
t
L(t, x; σ) i
sp
o
s
i
t
i
v
e de五nite i
n [0, T]xRn-lx[0, 0
]
. From t
h
ef
o
r
e
g
o
i
n
g
1
.5
)h
o
l
d
sf
o
ru w
i
t
hi
t
s
p
a
r
a
g
r
a
p
ht
h
i
s shows t
h
a
tt
h
ee
n
e
r
g
yi
n
e
q
u
a
l
i
t
y(
]
. L
e
tu
st
a
k
ear
e
a
lv
a
l
u
e
df
u
n
c
t
i
o
n cþ(Xn) ε
s
u
p
p
o
r
ti
n [0, T]xRn-lx[0, 0
C;;, (R~) s
u
c
hthatψ(ι)= 1i
n0 壬品三;'0/2 andc(
x
n
)
=
Oi
nxn"o
ands
e
tu=
。u+(l-cþ)u. C
l
e
a
r
l
yt
h
es
u
p
p
o
r
to
fψu i
sc
o
n
t
a
i
n
e
di
n[0, T]xR匁 lX [0, 0
]
andB(ψu)=Bu ont
h
eb
o
u
n
d
a
r
y
. Hence cu s
a
t
i
s
fe
st
h
ee
n
e
r
g
yi
n
e
q
u
a
l
i
t
y
(
1
.5
)
. Byr
e
g
a
r
d
i
n
g (1-ψ)u a
sas
o
l
u
t
i
o
no
fCauchyproblemf
o
rP(D)t
h
e
p
r
o
o
fo
fTheoremi
sc
o
m
p
l
e
t
e
.
F
i
n
a
l
l
y we remarkont
h
ec
a
s
eo
ft
h
eu
n
i
f
o
r
m
l
yL
o
p
a
t
i
n
s
k
i
ic
o
n
d
i
t
i
o
n
.
a
t
i
s
f
yt
h
eu
n
i
f
o
r
m
l
yL
o
p
a
t
i
n
s
k
i
ic
o
n
d
i
t
i
o
ni
f and
The o
p
e
r
a
t
o
r
s P andB s
o
n
l
yi
font
h
eboundaryannc 十 a,, >O andt
h
eq
u
a
d
r
a
t
i
cformH(σ) i
sp
o
s
i
t
i
v
e
de五nite (
S
e
et
h
e remark o
f Theorem 2
.
5
)
. Then t
h
ef
o
l
l
o
w
i
n
gc
o
r
o
l
l
a
r
y
f
o
l
l
o
w
si
m
m
e
d
i
a
t
e
l
yfromt
h
ep
r
o
o
fo
fTheorem(
e
s
p
e
c
i
a
l
l
y(
3
.
1
5
)and(
3
.
1
7
)
)
.
h
a
tP andB
Corollary. Suppose t
sati.めI
t
h
e uniformly L
o
p
a
t
i
n
s
k
i
i
c
o
n
d
i
t
i
o
n
. Then t
h
e
r
ee
x
i
s
t
s ap
o
s
i
t
i
v
ec
o
n
s
t
a
n
tK s
u
c
ht
h
a
tfor eveηy
r
e
a
l u ε H2((0 , T)xR~) t
h
e follo叩ing e
n
e
r
g
y inequaliりI h
o
l
d
s for any t
(O<t 三二 T):
:
1
((u(s, "O)))~ゐ
(320)iu(t,)日+
豆 K(f}Pu)(s,. )rゐ +):(((B州,州
where
((u(t, ・, O)))~
Remark.
= ((u(t,
We 五rst
2 , /åu
匁
・, 0))/+ ('
:
"
"(ム・,.,..
0)))2 十 L:
一 (t, ・,
。t ,.
l"藕 j
(
(
0
)
)
)
2.
p
r
o
v
et
h
ef
o
l
l
o
w
i
n
ge
n
e
r
g
yi
n
e
q
u
a
l
i
t
yo
fh
i
g
h
e
ro
r
d
e
r
.
For e
v
e
r
y u ε Hm;3((0, T)xR
'
:
) (m 孟 0: i
n
t
e
g
e
r
) with Bu=0 on t
h
e
n
e
q
u
a
l
i
t
yh
o
l
d
s
:forany tE(O , T)
boundaryt
h
eene棺y i
(
1
.5
)
'
i!lu(ム )11i:.;2 ~K(llu(O, .)
:
1
1
:1
2+1
1(pu)(O , .
)1
1
1
:
+j;111(Pu)(s, )ii;1 ゐ),
where
I
l
l
u(s , •)
'1 ,ト到す仏
)I[
j
I
t su伍ces t
op
r
o
v
et
h
ec
a
s
em =O
. Thedi旺erence betweent
h
ep
r
o
o
fo
f
OnEne γ部 l
n
e
q
u
a
l
i
t
i
e
so
fJ/li
x
e
dPγoblems f
o
rHyþelも olic
E明 αtions
o
fS
e
c
o
n
dOrde γ
蛄
蛄
~U i
n(
3
.
4
)and
藕k
(
1
.5
)andoneof(
1
.5
)
'i
sa
sf
o
l
l
o
w
s
. Rep1acingu by -~~-,
。t
;T>
¥
主主も
~
moreoverBu=Oby -,!:- (Bu) ニ 0, -:!-(Bu)=O(んニ 1 ,… , n -1) respective1y, the
蚯
藕k
following remaining term a
r
i
s
e
s from (
3
.1), (
3
.2
)and (
3
.3
):
トtト;〉〉<《(QQ
伽
lバu州 tι
川川,
刈,,叫仇)
0) , 伽
where Qj(
j= 1, 2) i
s aj
t
h orderd
i
f
f
e
r
e
n
t
i
a
1oparatori
n ~ ,一一 (k
。t
藕k
<n).
Using the t
r
a
c
e inequa1ity , the above i
n
t
e
g
r
a
li
s estimatedby
K{εIllu(t, .)1 ,1: +C(ε)Ii:u(t, .):1 ,: +!I;u(O ,. )
1
1
:+i:lllu(s,. )1::ゐ} ,
r
b
i
t
r
a
r
yp
o
s
i
t
i
v
e number. To estimate _~2て
where εis a a
dX;'
we
usetheequaュ
t
i
o
n(
1
.1
)
. Combining these f
a
c
t
s with our method i
n ~ 3 we obtain (
1
.5
)
'
.
Second1y t
o prove the e
x
i
s
t
e
n
c
e and the r
e
g
u
1
a
r
i
t
yo
f the s
0
1
u
t
i
o
no
f
our prob1em we use themethod o
f approximation. In fact , by theassumpュ
) a
)
e-b2 i
sp
o
s
i
t
i
v
e de五nite , the condition (
C
nd (
C
t
i
o
nt
h
a
t ann>O and an
1
2
n
are e
q
u
i
v
a
1
e
n
tt
o annc 十 a n 孟 o and annc+ 正1n ~ the p
o
s
i
t
i
v
e root o
f H =0
with r
e
s
p
e
c
tt
o annc+ ιHence P and B are approximated by P and Bε
which s
a
t
i
s
f
y the uniform1y L
o
p
a
t
i
n
s
k
i
i condition , where
dX
n
.ι -(C+ ε)p+h.
,
藕j
Bε=Y-21bj ・
j工l
蚯
References
.SHIROTA: On n
e
c
e
s
s
a
r
ya
n
dsu 伍 cient c
n
dT
. AGEMIa
o
n
d
i
t
i
o
n
sf
o
rL2-wellュ
[
1
1 R
p
o
s
e
d
n
e
s
so
i
x
e
dp
r
o
b
l
e
m
sf
o
rh
y
p
e
r
b
o
l
i
c equations , ]
o
u
r
.F
a
c
.S
c
i
fm
0
)
3
3
1
5
1(
1
9
7
HokkaidoUniv. , S
e
r
.1, Vo.
l21, N
o
.2, 1
[
2
] M.IKAWA
r
o
b
l
e
mf
: Am
i
x
e
dp
o
rh
y
p
e
r
b
o
l
i
ce
q
u
a
t
i
o
n
so
fs
e
c
o
n
do
r
d
e
rw
i
t
h
a 五 rst o
r
d
e
rd
e
r
i
v
a
t
i
v
econdition, P
u
b
.R
e
s
.I
n
s
t
.M
a
t
h
.Sci., KyotoUniv. ,
1
9
1
4
7(
1
9
6
9
)
.
l5, N
o
.2, 1
S
er
. A, Vo
[
:
l
] M.IKAWA
i
x
e
dp
r
o
b
l
e
mf
r
d
e
r
: On t
h
em
o
rh
y
p
e
r
b
o
l
i
ce
q
u
a
t
i
o
n
so
fs
e
c
o
n
do
w
i
t
ht
h
eNeumannb
o
u
n
d
a
r
ycondition, Osaka]
o
u
r
.Math., Vo.
l7, N
o
.1,
2
0
3
2
2
3(
1
9
7
0
l
.
[
4
] M.IKAWA
: Mixed p
r
o
b
l
e
mf
q
u
a
t
i
o
nw
b
l
i
q
u
ed
e
r
i
v
a
t
i
v
e
o
rt
h
ewavee
i
t
ha
no
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