Smoothness for Strong Solutions of a Hessian Quotient Equation

 万方数据
数
进
学
展
which arises in special Lagrangian geometry:ifⅡis
in C3 is
This
a
a
33卷
solution
graph of Du
of(2),the
oVer
R3
special Lagran舀an submanifold in C3,i.e.,its mean curvature vanishes everywhere[引.
special
case
has received much attention.The existence theorem of the Dirichlet problem
in【4].In【10]and【17],Bernstein theorem for the minimal sunmanifold
(z,Du(z))were independently proved.Recently,Bao and chen【1 J obtian the regularity for strong
solutions of(2),and show 3 is the optimal sobolev exponent.It was shown in【16】that c2,dmorm
of
solution to the equation(2),not necessarily convex,can be bounded by its c1,1-norm.
to(2)haⅣe
ob七ained
been
a
using urbas’s ideas
Theorem
with
in【15】on
reglularity of the Hessian equations,we have
Let几≥3,u be
1.1
convex
a
p>堕竺≠坐.Then t上∈C1,1(Q)and
Q
the above s01utions
Remark 1.2
equation(1)in W答(Q)
ID2仳f≤C,
7
on礼,南,c,p,Q7,dist(Q7,aQ)and
are
of the
for any compact sub—domains Q7 of Q
sup
where C depends only
strong solution
the local Lp・norm of D2u.In particular,
smooth.
There is
an
ex砌ple
show that Theorem 1.1 is false if
to
p<n(cf. [2]),
which implies that this regularity result is optimal for n=3.
If礼>2七or礼=3,Theorem 1.1 improves Theorem 1.1
with
with
in[2】,w王1ich
is
the analogous result
theorem will be proVed by showing that if
p>(n一1)max(礼一庇,2).The
u∈I矿2,p(Q)
p>竺墨半,then we have乱∈w’2,;(Q)for some芦>(扎一1)max(札一惫,2)(谊fact,for any
above
F<。。),and
therefore the conclusion follows
In order to proVe Theorem 1.1,we
the m01lmcation u£of u,which allows
use
us
to
Another approXimation is using the second
from[2】.
twD
kinds of apprcodmations of the solution u.One is
apply Reilly’s forHlula to obtain integr越estimates.
di艉rence quptient△是¨to
dealing directly w王th the fomth order Weak derivatives of
The
rest
of the paper is diVided into
part
replace D2”,which avoids
t上.
in the next section
tw.o sections:
up
u
appro)(imations.The last section is devoted to the
theⅣ2,p
solutions to the
2
local彬2,芦⑦<∞)regularity
of
and its
equation(1)with p>兰%型.
Preliminary Est imates
we
always
ass啪e
equation(1),and
Q’is
that
a
non-negatiVe function in
u∈皖?(Q)with p>巫专丑iS
0c。nvex
compact suKdomaill of Q in Rn.Let妒be
c。o(R竹)vani号hjng
outside the uni七ball
a
str。ng
Fbr£>0,the regularization of
u
is
solutio|1。f the
mouifier,that is,妒is
Bl(o)and satisfying
妒(z)dz=l
de王lned by the conV01ution
姒小£一正妒(半)岫№=k咖M…州s,
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we set
notations and estabUsh preliInjnary uniform estimates for Various quantities inVolving
a
万方数据
学
数
To
get(o?)>o,we
have
进
展
from the e11ipticy of the
33卷
equation(5)at
t正£
0<(一(嘲)=(渊
≤(渊 )扣1再篙网
、点-1 s碧(D2u。)s≈(D2u。)一sk(D2u。)s?(D2u。)
//
Here we haLve used the first inequality
Lemma
Let p>n~1
2.2
estimates in Q
(佗一凫)s2(D2u。)
in(7).
and£<dist(Q’,aQ),then AE,A£and兀satisfy
壶≤入。s(跳)一l,
△u£
C
△u,
C
where C is
Let入1,入2,…,入n
Proof
is
omitted for
(9)
≤兀≤n(△u。)“一1,
on
n,南and
(10)
c.
be the eigenvalues of D2u£,here the s・dependence of the入j’s
simplicity.Without
10sing aIly generaUty、Ve may
and D2uE is in diagonaLl form at
(s?(D2t‘c))are
(8)
茎A。≤(△u。)”一
positiVe consta皿t depending oIlly
a
the following
7
assu】me入l≥入2≥…≥入n>0,
the point under co璐ideration.
Therefore,(砖(D2t正E))and
in diagonal forms as、Veu,and
ao飞、
c。耻aiag(瓮一c舞, 瓦叫瓦’…’瓦叫瓦J
。aAn/
a盯n
a盯七
a入2
。aA2’
a仃n
’aA竹
Moreover,it follows矗om(7)a11d(6)that
入筹;
糕≥瑞狐
入1…入k一盯&(入)一’
A,≥.一≥A*+,≥占, △u≥丢,
(11)
and
A1…入kA嚣一。≤盯。(入)=盯k(入)丘≤cAl…Ak^,
in turn
A。≤C(丘)^
Therefore we have by
(7)and(11)
M。=入-(瓷一c舞)=仃。一cA・舞
≥c(一A-舞)…羽M..^)
狲。…k。≥丢,
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(12)
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3期
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mpletethe
we co
of
f
o
part
rp
thelemma.o
Theremai ning
f
o
of theproof of thefbuowing result. Propos
tllis∞ction consists
n≥3,p>二!g;F盐and u∈I再《等(Q)be
hve u∈V矿翟(Q)for any F<oo,and for any conlpact
n
3.3
Let oitia
of(1).
there
Then
e xists a
we
positiVe constant C,dependiI培only
on
coIl、rex
solution
strong
subdoma妇Q’of
n,南,c,p,芦,Q7,dist(Q’,aQ)and
Q
the loc越
工p norm of△u in Q。sudl that
D2t上IILF (n,)≤D
Proof
where p∈
L et上hR(∥)c
僻,2R】.Applying
Q7.wb
begin with
the sob。lev
(k)(u产 )格ds)署
阬㈣+("≯)黜)ds)勰,c(t,(
s
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soⅡle
integral e8timat∞on the sphere
ineql】蛳【10'Theorem2.11
0n
aBp(可)for
t,于乒
aBp(可),
3期
保继光, 李美生:
Smoothness for Strong Solutions of
a
Hessian
3ll
Quotient Equatlon
that is.
(L,u∥ds)攀ck,(胁≯l端+u掣铲)崛
where C is
a
constant
depending only
Take
It is
on n
and R
q=锱
clear that q>p一礼+l≥1 since
p>坐≯.By
YouIlg’s inequality
and(10),we
u:兀≤u掣+兀尚s口∥+n群(△t上。)p—n+1兀
u:兀≤%“一2
+兀“一1 S%“~2
wb combine(21),(26)and(25)to
(25)
+n’茳f。(△t上。)p一“十1兀
obt越n integral estimates
on
the b越l
have
(26)
Bp@)
(k唧)一s c(k,一叱,旷%州z)一
c(k,(u掣m¨一+1兀)蚪L矿1舭)一
c(k,秽攀ds)谢
+c(k,c蚶一1椰+L咿1叫如)一
s
5
≤ck,(1。t,≯l渊+u掣掣)ds
+c(Z引掣,(△‰)P¨1兀ds+五加,《ql吼l如),
where c stands for constants depending ollly on佗,七,c,p a11d R,and we
ha僧used(10)aIld(11)
conchlde
to
(△u。)p—n+1兀≥丢.
Integrating the above inequadity
aver
p∈【R,2嗣,we
(27)
arrive at
(k似)帮
≤cL,(1。秒≯I掣+"掣铲+(△¨一托删1乳f)兆
(28)
万方数据
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3期
Smoothness for Strong Solutions of
保继光,李美生:
and C
denote constants depending only
on
a
Hessian
Quotient Equation
313
n,后,c,p,R and
△“%掣(B。。(Ⅳ))
By the
sobolev imbedding theorem,、ve have
de矗nition(1 7)of"£and
%斗△&u,
Letting£—'o
uniformly
in
B4R(耖).
in(30)for 6xed^<dist(B4R(可),aQ),using(4),(13),and(20)we
obtain
(k c如,a他)÷s k,(c啦广州小妒…-m,
c
(31)
where
n2一n+2
S=
>1
(n—1)( n一2、
Now、Ve choose∈to be the coordina七e directions ef,f=
l,2,…,n.By[6,Lemma 7.23】we
ha怃
I}△兰。。钍II二,(风R(可))≤}Inf"llp(鼠R+.(Ⅳ)).
By the weak compactness of bounded sets in
to
zero,such that(also cf.
Lp(B4R(y)),there
of【6,Lemma 7.24])
C he pro of
△象。t上一D“u,
using the weak 10wer semi-continuity
weakly in
exists
a
sequence
Lp(B4R(耖))
{b)tending
(32)
in妒(B4R(可)),we get
{B一 ㈨m№≤1骋警厶。础)峨一u№
’’
(”)
J—+o。‘,B4R(可)
<~
l
.Ⅱ.J
n_ .盘∞
f
/
J鼠R+^,(可)
lDffuIp如=/
lDfluIp如.
-,B4凡(v)
Consequently,
、……’
土恐忪‰;u怯(风只(Ⅳ))=jIDffu怯(风R(y)).
一……
’’
,。—+。o
Therefore,applying
Radon-瞰esz
Theorem【8l,we h制|e
△‰lt正叶D“u
It follows from Fatou
in
Lp(B4R(暑,))
Lemma,(30),(33)and(13)that
(正R。。,I。“ul。7_。)÷≤・≥马娶r(正。R。v,l△‰,ul。7_z)。
<C
——
<C
万方数据
(33)
1骋簪五。小)((△象。u)p—n+1+(△u)P一¨1)丁dz
正州√酬P叶1融
(34)
314
数
学
33卷
、{
/,r
l/
\',口R(Ⅳ)
a
展
the iteration formula on△u in the integral norm weighted by丁
Thus we arriVe at
where C is
进
constant
c五。舶,(酬P叶1丁d茁,
1
(△u)a丁dz
/
depending only
on
(35)
n,南,c,p,R and
△u忆鹄≯(B:R(p))。
Noting q>p一礼+1
and(35)holds
fbr a11y
p>!!i:≥墨立,it
can
be iterated finitely many
times to yield乞he desired estimates.In fact,for aIly preassigI坨d nuIIl_ber F<。。,chooseⅣsuch
that
where
F≥圪Ⅳ(p一佗+1),
Let
R<虫掣Ⅳfor
K=南>1
p—n十l
the c。mpact sub.d。main Q7。f Q.By
iterating(35)Ⅳtimes,、ve。btain
丘舶,(酬吼z s厶础,m广(p-时1)他
≤(cL√酬∥b…他)8
∥(G正。:小,c酬扩2(p-州慨
52
一~叶sⅣ(Lo妒州他)∥
Therefore,we
obt豳by(10)and(11)
/
(△u)p7讹
(△t‘)p如≤c/
JBR(!,)
',B只(掣)
≤c(Lo妒州做)。≤c(小妒如)”,
where C depends only
3.3
We、阳uld
on
on
n,岛,c,p,F and dist(Q’,aQ).This compkte the proof of Proposition
by applying the flnite co、rering theorem.
ln【e to point ou乞that the coIlstant C abdve,hence in Proposition 3.3,depends
F therefore Loo estimates for△t‘does not fouow directly by lettiIlg F-+∞.
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万方数据
in
dimen8ional three
Jnd‘口n口c,nit,.^f口t^.JDt‘r..
and regularity of
a
Hessian
quotient
3期
李美生:
保继光,
【31
caffarelli
L
Smoothness for Strong Solutions of
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A,crandall
swiech
A.On
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一个Hessian商方程强解的光滑性
保继光-,李美生z
(1.北京师范大学数学系,北京,
100875;2.北京航空航天大学应用数学系,北京,
100083)
摘要:我们获得了一个H蝴ian商方程w2,强解当p>掣时的c-,-局部估计,并证明
了这些解是光滑的.有反例表明这个正贝lj性结果在n=3时是最优的.
关键词:G1,1局部估计; Ⅳ2r强解;He∞ian商方程;光滑性
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