Instructions for use Title ON ENERGY INEQUALITIES OF MIXED

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
fH(σ。)孟 o anda
n
n
c+an<
0, t
h
e
r
ee
x
i
s
t
sareal りo
s
u
c
ht
h
a
t R(旬。, σ。)=0 andC(!', σ) i
sn
o
tboundedi
nanyneighbourhoodof
(勿0 , σ
ω心0)
向
I
nt
h
ec
a
s
e伊
(iii) wema
可
y 出
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
'
"
"
- "
'
/
" --,.,."
"
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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c
t
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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一
,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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ef
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
<>
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
2
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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。
. -, .
/
u
Le
te(~_) bet
h
es
q
u
a
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er
o
o
tof
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ith posi・
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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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