5 Rùi_arioñs
t b
lvhere
I ôuthe infimum is taken over all u e Ct, with Ll¡o:,I, yu:
âtt' \
:lñ' 'ñ)aud
rvhere,in the particular
casey':
n,, t1'e support S,,s
Ro).citY.
f .ol
Corres
CR'
C*(F) : linf
I !o(¡
-
t)idp.(x)rtr¡(y)I'
s'here
lirn
<Þ(r): +co un¿'rtr. inlinlrrn is taken over all the
me¿rsrrres: I altd tire
sr.rppor-t .S,C
F.*, L; rvill lrt, thc
vc'ctoripace o[
Iunctionsf(r) >
0rf
@is a ker'er, then, for r<þ (
co andEcR,,rve
crefine trre caþncityt't'lrcre
J' = f.i
anclthe
convolntiontÞxf(x)2 | Yx =8.
A
Co,¡ furrctiort (È-).\\ie / u'hich
remincl satisfies theseilr"i-ir."-ì.u.,ãirtio,l
conditionsis
calleda
testfunclion
torI <Þ,rf(x)
:
5 (Þ(*-
y)f(y)dt,.. r-et
ü)L+(E) bethe
coneof all Raclo'lneasrlres p à 0 carried
Lty E,i'e' with ulR" -
/'r)-
9, .anð.LI!E) its
s'bspac""o,r,por"d
of
arl r'casuresp rvith
lirrl.l.= tíe totat ,rariaïib,í
åì. ¡.r,< o..
Fof
¡r,= ti (E),
we havethe
conr.olution!*,.
bethe o-argebra:I:iii],:j,,iÍ;JÏÍl];abie ror
e\¡ery¡.r
bero'-
gtngto
the corre srli+ ofall posiii""
nàãu,.l rneasrrres.For E e ß,,
rve define^ure,t"ot';f ¡t;, i;;;;;,t,;g
cøþac,ity.ca, p(EI
: sup
llr¿llr,c:a,þ(E)
: hf llfllf,
Il,fll- :
essstlp lÍ@)l <
"c,llÍllp:l\f@)þttxlþ < ut, I < j, < *,
OT
l¿
th
¡-r,(R")1<
nreasurable
> 0
r'r'i14
Þrrnuc¡.n¡'MeÑ '
21
V(i.e. for'afly) P>n- 1, 1ôg-itt and ttt':'1,'?,"' anil àlso"that
'f tu
Co(Eo)
:0 with
V(i> n-l andm:1,2,'...
But I
obtain even lrrore, i,e. sorne inclusion relatious betlveen Hausclorff h-rneasuresand clilferent
kinclsof
3essel capacities, gencralizingin
this rvaythe
corresponcling theoremsof l.
,rr.¡tr¡ls and N. \IrtYÉRs[2]'
Sorneof the
inclusions are shou'eclto be
beimportant lemma of du
Pr,DSSrsrelations,
I
deducethe
correspon clorff h-meastlresor
Bessel capacitieNow,
let
us recal1 different conc Hausd.orff h-measures and.the
diffe'[hc
þ-moclul'usof
cLn arcfamit'y I- o[ a
domainD C R"
is. Mp(l) : ttlt t
P(x)o clxrvhere clx
is
tjnevolum
element andthe iutimum is taken over all
Borel,n"oiutobl"
-lunctiousp(x)Z 0
suchlhat
lpdsì 1 Vf e l''['he
i¡-modttlttsM(l) : M,(l) is
"tllecl ,iropty ,nod'ol,rrr.i " .
'À tor""omorphism f :D?D* is said
to'be:'IÇquø'sièonfornt'øl(!'s
Sl(<oo)if
,j¡¿(r)
S ¡/1t*) <
/(,1,1(t), l(Ivhere
I is an arbitrary
arcfamily
containedin l)
and.I.*:,/(f).
ì,Û1ne Hailsd.orff k-tùeasure Hn(E)
of a
setE C R'* is the
non-[egative nurnberHn@):lim
iì1r>,,,,h1d(n),,')1,' ' :
'ù+0 {Em}
rvhere
the
measurefunction
/øis
supposed.to
be continuous, lQn-ne.gAtiv-e,"áä-a""t""sing in
sorneinterr.al (0,V'),r'¡
0, and- suchthat fu kl'¡:9,
and
wherethe infimurn is taken over all
countable coverings{8,,} of
Eby
sets E,,,havinga
d.iametei rt(É-;,,)Í 8. " ì I
,The f-cøþacily
of ø
comþøctiet p 6 R" is given as
i :, capnF
:
infi
I,Y q(x)lþ dx,flcÍ r S
r,,,,I
)'
1
fn fl-2
1 f
/u
1il-1
n
fit-I h:2
n
I
/
fn
I
1o9,,)'
1og,
logo logo
il-
ißforrgr,,,
1og
log
(2)
o(z):
fl-2
)"-'
(ii)
cE,¿(E):
[Co,p(E)lþ Y
ønalytdc sct E.(For the proof of these 3 propositions, see N.
,)rnvnns
¡12i.¡Corolløry.
co,p(F)S
[Co,o(E))o VE ç.R,.
r'deecL,
from the
precedin! 2-proposäions, we deducethat
I
cø,p(E)
: tîp
cø, p(F)s
;**,¿(G) :
c6,p(E):
[co, p(E))o ,rvhere
.F
a1e compact andG arc
op(11..Now, i' ordei to obtai.
Bessél capacities, .rve shalrco'sider, in
theÍ:iii:råri: of lhe
capacities rronr above,^thepaitic"l", L"r""i oúi:;fr)
The kernel g"(r)
>
0 is astrictly
dec'reasiug furrction oTr :
lø1, continrrousoutside the origin' r"u"îrrt-T),:;"t *
;;:'. -,
g,(*) -
log .1- ,whilc.,
as
-Í+ co, l'l
(3) Ko*88:
{q!,()(cf.
lor
irrstancc N. ¡rEr¿ERS r12l).And'
nor',
oneintrodu""r
tn-å3 ki'ds oÌ
Besscr, utþøcitiesBo,þ:
Cro,O, Ito,l,:
cen,p,lo,p:lro,, ropositiol
!.
CafiE -0 iff
(i,,c.if
ancl, ontyif)
thcre cxists ctfun,ction
Í = Lf
suclt, thattie
i,ntegral( ,Iu\,|/^=:* yxeE,
J lr - yl"'
taithout being,ictent,ically infinife.
2 - L'analyse numérique et Ìa théorie de l.approxibation _ Tore Z _ No, 1/t9?E
0<c.3tt
v
t
(i)
cg,e(E):
[Co,t(E)]þ yn.,,
1!q-r-l
I
ehÈlÀrioñs 5
*
q-n2Proþosition.
3.
We høve' g,(x): -J-
,: ,,,*+r[]!
S"(x)
- lxl 2
e- ti,
Fot ø,
P> 0,
we have alsothe
relatjon16
rvherq
¡r e Zf
1E¡wittr
' i
ll<Þ*¡'r'llr;<1,
,,1,
Þrrhir can¡.i'i¡.ñ
+
I | 1-1
þþ'
t: t
'tì ri' , j
c6E:cø,{E) -sup, lltrll.,, ì ,,,
l, , ¡ i,
the
supremum being taken overall V = ü (n)
suchthat
(Þ*¡r(ø)
Zl Vx e R".
,
,Such
a
¡.r,is
calleda
test ,ne&surefx
crÛ.v
is
called a c*-cøþøcitu'y dístributioi ¡'or Eif it is a tãst -"ur,rr,J Io,
co ancl llvllr:
co(E). :, I ,rI,et us
definefor all E C
.R',cg(E): inf
ce(G),'G>E
g'he¡e
G
are open sets.For
-Ee 9r,
clefinel}re
caþacitSnch
a
¡,r.is
calleda
¿iit, rneasu,retor
õr,o(tl).If
C is a capacity and. &its
domain, i.e. a class of'sribsetsof
R,'whiöh containsthe
compact sets randis
closed under countabie union, Cis
calieclan inner
caþøcityif
E e
€I+
C(E): sûp C(F),, ,
¡t:t,.' 'F , ,' ,llr.
being taken over
all
compact sets F.C
E.C is cplled an outer,7.,p(E): sup
llpllr,rvhere ¡,r, varies over
the set of all ¡r e f-{ @)
suchthat
t'o*(ox¡.r,)t-l
(x) Sl Yn
e- R".the supremum cøþøcity iL
. ,J
E e
,91+ C(E): inf
C(G),'G
the infirnum
beingtaken over all
open GI
E.Proþositiotø 1. Çø,0
is
øn outer caþøcity.Proþosítion
2.
co,pis an
inner'caþøcit1t.18
pErnu CÀR^MÀN(For the proof, see JU. c. RESÐTNJar [16], rr. 'wALrrrN 122, 231,
or
Y.rurzlrra
[13].)Corollary. Cap -E
:
0+
81,,, (E):'
g.fn
orderto
irnprove someoI I) ;\r)-\lIS
atttl\r'e tra¡,'e
to
introclncethe follos'ing
kentels :8u, þ-\, rr, g(f) :
g.(r)^q'ft.r,
l'lt'
'11.,,',,,t
¡u
to, )'!
r,,,,To
c1othis, *'e
ucecl-t_o ìrr'estigate
the beha'ior oi the integraut
onry atr : 0
andx, n. \\/t.
lravc.6
s. P. PrlnoßleZnNsr<ri [15 l,
7
1
gþ.'@)g"þ:þ- r,^,çt(x)
- l:vj .ã
,,' I'lIìËLÀTIONS
(r.*^¡j, )-'[ros,,, ',
19
,x rrtivl;ls
['2]
resLrlts,0<a.<rt
þ'
þ-- t ut- |
À'-l
n
as I --t, aDanrl.
, \ fs"{')(rog t')o '-t:l ('"- ll' 'i.'o*"'
'|)u '"' t' !
1""' 8t, þ-t, r', ß(// .:
I¿>n'P-''nt"1\
t
[r,,{,')[ros
),,,,' 'ji, (t"*-,i,)' '1t"',,,;';)u t"'
v -;> )'¡¡¡,rvhere r.,, is here as v¡el1 as cverrvhere
in the
L)al)cr suchthat
1or{,,,I
-'r-
L
ft
is easyto
see thatgo,¡
t,bt,() loÍ o.I n
arc kernel:; (:rct:orclirrgto
thJ"'abor-e cl.efinition).'.lhc
corresporrding capacitiesu'ill
bccro,þ- r,r,,B -"= b{o,þ-1,ril, ß')' cio,p t,tn,þ: 13çr,¡ 'r,tt,¡"1' 0 ¿:- '1" S lt'
luenrrna I If t"
e,9lL+,d.þf n ancl ?.->þ -l,
llten'ancl
þ'9
Bþ"' U)g".;:r,-r,,,.8Q)
- lxl,'n' ¡rorol J-'
/tog,,ll --
as .r
-,
0.^-rI
'l.vl/ \ ""'lrl
/åt"1iJJt" to
st:e th¿r1 thcse2
relations iurpl_ytlie
prececling inccFralit\., asRentttrlt''llhis leltlnta g'c'c.ralizes a re,sult <¡f rlu pr,llssrs ¡1rll, as l'.11 ¿rs klnrna ÍJ.l of ì). aDAtJS
n,ù x, rrrivlins
i2 ].Propositiou 5. tf J
=1.þ, then,for 0,<s{n,2<.¡,{
co,f ,,(,r) = \ --l*A2q-- <
"o
; '
l.r- ),!" I
eueryz,lt'cre cxceþt þoss'iltl.tt'i,,
u
s¿tÌi
u,trticltis oJ
c,þttcir-tt(:pli
- 0 vrj >
=
,,,*
q". zøltert Cg:
L'u, zuitlt <Þ(r) ,_.¡.
(t.(-rror ure proof, scc
\.
rltr l)lcssis ¡14,, ilrcorcrrr {)..\s
¿r clirectcollseclr äi"g-ì;;rr",,',u"
har_cthc
iollo- rvirrg gerreralization"c;,.
oI^.tloi'y'.'t¡¡ = ïil]'l:',,,,2 < þ.i,tt,,it,t,
ttt,tL,t.(-'k,/(v) ,=-0Vp I
os eueíy,zptirí,,,
> þ - l-qtul 1r:.
1,,¿,... st/ jì
zu'illt [JGp,p,,.,¡n'Ii).:
ror.c
it is
1¿tlsc,,tÌrat
go x/(;v) =-. coirr a
bouurlccl :,,{¡-,,r,,tlet
¡_r.} 0 bc a-rìróarur" rvith
¡-r(ll,):
,t
i,{"¡,r
r, ¡¡, ¡(.r
-r ) r/¡r(_r) is
lrounclcciirr
/1,,.,ccer<liug proposítiori ¡rnil
-bv
rl(.ans
ol thc
pre_thal.
\go,:,f(x)tlp.(x)
= llf
tt,p,1',(,,i,p.ll¿,5
ti.l ,;pQill:,p,þ t,,,t,L\*
1r¡i)'.,: ,.,
cotltra<lic1 irrg
thc
hyllotht,scs.Rett¡ttrh'
Dtr
Pióssis' 1rt'ool'ol' lris
1h,,,r¡rcur4
(corrcsponrli.g t"cr orrr llrccedirrgpro¡'osition) is
incurr.cc1..I{e
¿rsscrtsilrat Ii
Li iu
., -,,; "
.,.i
,",t/u(l)i',' r('lltlìra l), '.r/.i:]- brri flrc .ico (:oîr(sr,r,rr,li'g,:*¡,."*rin,,
as rr (.()rìs(.(llr(.lrt.r.oi his
rt.urrna (gcrrcralizerrirrr..lr..cf í,;-'iri--'ì",;íi,,,ì"i,
5r. otrrlj,lll^
Lntslact - 'lt!-'" is
..r,i,ñiâi ¿v(s)l" in
',r.t,,*'rrcLe.Stlit.
frunL, is s*PPoseclto bc
¿r bounclecr sct, a'clt
e.?) Ia
iog¡u-7
1
1' ,,,
I P,
1og,,
loÍ r
-> r,,,,(nt.:1,2,...)
llg. x trl lo,
I
Q llgop,p
t,zr, B >t ¡ri lþ llttllo' Qis
a. cr¡trstn,nl íncleþendent o.f V.arñ ]- |
,l;;
:
tIlolcler
incqr-rality yieldsg. *
p(r) :
(g, gop!p t,Dt.p 'glp,¡
t,,', I ) ':' ¡¿(5¡ 5_!:11
S t(gl'
'g*p!r-p,,,,s) x ¡r.(ø))þ'Lg"p,þ 1,ilr,pJt, p'(x)lþ llhrrsþ'
llg.*rr.ll¡, f
t \et:'(x)e"p!p.-1,n,þ(x)i(x)lF llg"p,p,,,,8 d<¡.rlllllrrlll
It
remainsto
shou'that
þ'
Js!"' (x) eø: p - r,,,,s (x) d x
<.
rr'i
1 I
j
I
j
I I l )
)
'J
Remark.
This
theorem ,generâlizes D. ADArrsand
N.,ùIEVERS theo- rem 3.1in
[2].- . l*rom the
precedi4g theoreurand the corollary pf
proposition4,
rvededuce
the
,c 9. r. o I 1 a r
y. In
the kyþorhescs of thc þreced.ùry rrreoretn,,ue
haae lhe inequalitiesBr,,¿(E)
S
Bs,,,-r,,,,p¡(E)<
Q "up Ë
(rn:,1.,2;i,.i..).
Proposition 6. VECR",
Co(E)>0 or "ö(E) >0=H,(E) :
(The
proof irr the
caseC6 is given bv S. -I. ,Iaylor llgl
theorems.1
and 2 rvhile, for the
casei'5,
r,vcmay
usethe métuóaò'oi
chap.rv in carleson's book t8l and the capacitability results of n.
Fdgledet10l).
Theorent.2.
Let 1<q <þ < æ and þ 11, then,
,,r,,,B*,¡,{ H, {
P ¡,,p,,_ r,o,,0)d B1rr,ø),,(rn: I,2, ...),
l;Ve
!'a1te also Bç,,þ,-7,t,,,F¡
1
Bç,,p,Ltt,u;,g2).if nt,1nl,
ønd,for mr:
nrziÍ
Þr
(
Bs'2
capacitiesrvith the
same domain,or C is
strongerthan C')
and rvriteC'(E) : 0.
,We say that C
andã"t
"iålu
19'
ã $;L1ï'f¿"lt",t'r-i*
n C') and write
C'( C (or
C>
C').,.n.'
Tll.ir"losion
Bn;,6{ II,
was establishedby t.
aDÄ}rsqnd
N. }rErrERst¡i '-ä", "_::,::;'"n,s¡
'1' Bç','t¡is
obvious' Norv,let us
establish alsothat
and' B¡,,,7,, -l, rr, þ) corresþortd,sto
the 'hernel, t-þRELATIONS
{
1',
I 9,,(Y)
9,,(r) ukcre
h(r) :
:
æ and, i,f 9lo
À
n
ttt
log
t
)'
27
ttt-I
-"n
1og t
h:2
{t'*;;lJ-
[t"*, ,i,)-]
(. l\ ß-. : lros,,
; )
ror ,'r
3_' t',,,,rì-0"
|Q,gr,
--,,1 ïor , ?
1,r,..Z0
ÞEihUeÄÈAÀrr.Ñ
BÍHEoRrìM 1"
Let L1q<q.<û; dþ:n'ønd'þ>þ.-l'
lh'en'VEC C
RN,Bø,qt(E)
3 B6,p-l,*,
pt(E) SQB",p(E) (r, :2,3,
. . .),wkere
Q'is
ø constør,t't ind'eþend,entof
E:,øn,cl tke cøþa.citi' Bç,,q¡ corresþondb lo the hernel(4)
Bç,.¡-r,,,,,sJ(E)!
B¡,,,p-r,,,;,ri:"¡(E)if
mr1 m,
an;il,Jor m¡:
frtz,il þrZ þt. ' '
iFirst, let F
be a cornpactsetwith
b6,e-r,,,81(1l)>
0,If
test
measureror b¡,p-t,*e1 (n),
:tl,^t:"-
the
preceding llg.srrllp,s
Q'þllpllr',
llor
some constaut Q ind'ependent bfF.
Ifence, ' vthus, on
accountof
proposition3, 1
i,'
b¡,p'iti.,pl(¡-)
S QB",;(þ-)"" I'
rr¿hich
is
clearlytrue
alsoIo\
þ6,p-t,,,, Bl(F)=.0,
a-ud; siqÇe,01,,1,-r, ø,g) iÞì.4lrinner capacity and Bs,¡
ãtrouter'capacity, it
follolvsthat ,, I
:B ¡n, p
-t,,,
Bl(E) :
b'i,,, p- r,,,, p¡(E)
<
Q B", p(E)'
'Ihe inequalitY 'l
\Bç',
¡(E) 3 86,e-r,.,
pl(E)is a
cousequenóeof the îact that '
:71^gn,p-t,n,Bþ)
-
g.I 'i '"'-o 'g'' q(l)
Finally, inequality (4)
follows from¡.r. is a nou-zero lemnra
ï.or
r I
rr,lor r S
rr,g",i(r)
=
Lor
b",p(F), sothat
r-
Q.lim
ai I ,iij
We haue al'so
llull' <
b",p(F).¡+o gn,þ-l, rnr,gr(r) I ì(-2
;) Ð'"
s,Ø(tog
s"(z)(rog
:----l'
- Ir
a test measure,,dlilvri=Y,,,,',,'
gn,p-t, *",ß,(,)
=
const'o*-" :U,[,o*o-, (^r, n^riil' [,o*- , (tos2 ¡,"*å)l'
=
s
const.B,p(x)r[ (t"r,
i,)'-" (t"*-å)u:
const. Bar,p_z,n,e(x)Next, on
accountof (3)
and. arguing as above,(7)
1, s
rLj (t"*, j-l'-'1tos,,,1,u \ r,r* -
rùs,r¡_,t(3ld,ys
s
const.d (t"r- ¡,,)t-'(ror,,lr,lu s.nl*):
const. Bar,p,z,n,,s(x) Combining (S),,(6), (7)
yietds(B)
gu*
Eeþ-r),t,-2,,,,8(x)I
const. Euþ,þ.'2,u,,p(x)for lxl 3
2r,,dy:I r¡
I u,d.r:
go(x
-
y)g"rp-u?)dy
<I
ltl
o
øt
I lyl {lvl > p, lr-yl > p}
1 i
p
I u-l,l < p
RELATIONS
n-l
lylør-tr ¡
lt-l hr-7
:
corst, g"1t¡t"tl-tl
fl-1fl
Þ:1
s
const. S,¿(p)fl
1k-l
É const. g.,(p)p
,tr-l
11 23
!
s
dltl
0
7og^
ß
rog^
log,,
7o9,,
logo log¡
n
logo7og,n ( 0
u(þ-tl
2
2
d(b -1\
1-t
¿:l nl
I(5) /t <
const. go(p)I ,t"ø -
!)g,þ-r¡,p-2,,,,s,(2)ltl > rro +'.,
[to*u-, [r l"* i)i-" [tor,,-, (zøz r)]i
=)u=
(^rri,l'-'(
2t¡
t4)
1 \þ-2
t't)
tfl-l
-LJ [tor,
,ilo-'¡or. å i u,
ol'-"1
)'
ilt-1
8a*íaþ-t),þ¡z,,u,s(x):
\, r"@-
?)g"te_,r¡b,) lvl3¡'''' tn
(6) t, < ¿:r t fI (tos h-) t
\þ-2I
const. *-l,LI
(t"**í,)' '(
ttt_l
, 1ß
loB,,,
¡ I
Eq*8o(þ-tl@),
const. Sqþ,þ-2,.,8(*),2.
'I'he Ç6trse x ->@.
ì22 PETRU CARAMAN 10
Indeed, on
accountof the
preceding proposition,? ttt
\
r^,,,:,sQ)d,[(t"*
-i,¡'-'] =
.o,'st,0, ,,,,
i¡:r
log¿;J-'
(to*"' 1'I d 1og ooimplies the
desired inclusion.Remarþ.
This is an exte'sior of theorern 9.2 inr n.
AD..\MSa'd
N. T,TEYERS paper [2].
I,emnta2. If "þ 3tt,
thcn8c'F I uþ - 1), þ -z, r', g(x)
:
g aþ-
11, t, -2, rr, g 4 g"(x) S gaþ, þ -2, *, ø (x) )øncl
if I aþ
theþarticular
cøsesþ.:2 ol
in:1, ,/ p <
0,th'ett'
const. Í
gn ,, Eaþ_- t), þ.2, ,,, ø(*) :
ga(p t), t,-2, ,,,,,
i i' 'siù',
where^Ey,Þ-2, d jionr. thr'
'exþrrit',iotr,,i-à:", o:;,,,,,',
'[,y
nn:;"gþ - 'In 2
insteøorder to prove the
relation8a*
8aþ-t\,p-2,,,,g(x):
Sotp -t\,þ .2.,,,gx gn(x),
lwe
observethat
ga
*
íaþ_l),þ-'',-,s(x):
\ g"(x-
J') 1ott,,rt, p-t,ii,s (y)dy: :
\ïo(p-t),¡-z,m,g(N-
z)g"(z)d'z--
&uØ-tr),¡-.2,,,,o* 1o(x).u'lrete F'or we the
usedremaining the transfomration tí 2 iuequalities, - y: clearl¡', z,
hencewe
need onl1,!: t; -
z,to verify them as
r,-t 0 and
:v->
oc.I.
Supposefirst þ22 and, if þ:2 or r¡,:1,
assu¡re alsop=
O.I.l. The
casc^t
*0. Let 0 <2p - l:rl
S2r,,,; thet
gq*
luþ--t)
n-z ,,,g (x):
I
lrl u <-- '2&n@
--
j')gorp-n,e-t,^,s (it)d,y¡
8,þ -
!)8oø-rt,t,-e,tn,ø(y)dy-f
1a-e¡ al!!2
i
{u=\'t,-rr=\¡
j
g,(x -
j)EoØ-rt,p-r,*,pU)dl : lL + Ir*
Ia.I
const.,l], [t"*, l)'-'(^r^i)t ,-' 5
En(x,.!)snrp_,¡+,(y)dy
{lylÈp, 1."-rl>p} =
fi-l ,
<
const.[ (t"*, ài-" (t"*.;J'
B"p+t(x)I*l-u S
const, Saþ,þ_2,,,,s(x).2. The
case x+
co.|il_l
1. = II^ flo
t \þ-2t' t
ri' - Èi I gu;,)
ltos-;l go*gdþ-\(x) :
e"þ,n_2,,,,s(x).t, = -E' l^r,
n!,,1'-' ¡tor,,, r!,,)uwøl :
goþ, t,-z,u,,s (x).? ot
(þ:2,
þ{ 0), or
(nl: t,
I, - Iu,
allor,virrg rrsto
corrclude(*) S const.
gaþ,þ 2,,n,s(x) for.e ineclualitl.
if
1{ þ < 2 or
(p:
2,lirst
ø.'þ:
¡¡.= j:l
'
,,o^
,1,) (t'r*¡îf ls-r{*) -
const. s"f e)f
y,,-c,-.1 çty-
-
const' 8,,-*(P)I \r' 'arl=
,J],[,"r,-, llog
2| logri)lj-'[,"* ,,,-,(1og2 ¡
+ bg;)
¡; lr,,t*) - const.
go(p)p,, ø--
r:onst. S,,.-o(p)po-rl
à,(z
rogå)]'-'['"*,,,_,(, t,r;J]' ß,,(*) - const.l
ài)'-'(^r,, fi)'l¡t"øl - ) s,,@fà co'st
Bu,þ
2,,,,e @)For
ø1<
i0,we
have go*
gaþ_t),n:,_",,,,,g(x)
>th _l
à 1,
à s.(Bp) ,t=rll
l1og,\ -'Pt l)o-"¡tor,,,i)t I ""'pl o-' !
s,,o-,,u)
lylà',ry>t/t<p À:1
8,@
-
)')goo-ttb')dy-
l/l<p ffi-l
,tt-1 lt:1
n
til*
13 25
<p x-y
RELATIONS
lngn
1o -'(to*,,,
i)t t*,
,* goç¡-r1þ) -
s"(x -
),)Eoo-ubt¿yf
¿8¡
1r¡-l
plI
nr-- |
8e*
8uþ
1l,tr-'J,n1,A@)21r I Il
lilrl.' 't
ì
const.,I (r"*, r
const.t"ll,:+
-¡I,(t*^ );,,)o-'(^r.i)u
í',
5
const. 8a, þ-2,,,,9þ)=
const. gap, ¡ ,'2, nt, g(il)and, taking into
accountalso
(3),Thus, ga+ Ecþ-t),t-2,,,,g(x)
5
const, Kop,t
.¿,,,,ø(ri)for l*l > l,
'hehce andon
acCountof
(B),we are
alloweclto
coucludethat
ga 8 1uþ-tt,þ-",*,p(x)
S
co¡rst. gdþ,þ 2,,,,gþí)
et'er)'rvheLein the
caseþ2 2
and,iÎ p:2 or nt:
1,Ior l3l
0.II. Noq,,
1etus
supposel<þ<2 or (lr:'2,f3 50), ot (nt':l;
ß <
0).II.1. Tke
cøser *
0',U, [t.*,-,,los;- -
lost)l
[1o8,,,-,[t"i
-_lusslJesø(4 s
E [t"*,-,(î t"* i ['-'¡,o*,,,-,
(i t"* i
)1ur* t't
=l2
g,(x - y)g"ø-ttb,)dlt I
Bop, p-z,tt,s(x)dlyl
=
En@
- ùe"0-')(y)lYl' dY I
{lvl à p, lz-v lÈ p}
drS
g*(x --
y)g"tr-tt(s')dYI
l¡ I'l<p
g"p(x)
5
coust. 8ur,ø-2,,,,g(x) lvl <ptft- |
llla{r-t)-t l-[
PETRU CARAMAN
-'_
P 1
P
,lt-7
1r<fl
In S
const.g"(xl - t',)
1
P
,il-l
1
/t¡
const. f]
À:1 ltt- 1
,t:
n
IÞ
J
1ug
fttu
1og , 1og,,
logo logu logo
(
I
6 þ(t"*, ;l'-'(t"*. ùì)
,b-1
(t"u^
å r'-'
[tos,,,1¡r'
I
,, =T,lt"u, i)'-'(1o*- i
lu,-' I
1lt I g.(, - t)g,p-u!)dy I
gop't,-" ,n,s(x) l'rrl JJ ) ln
7 \þ-2
;i
tþ-,
(
a(þ- r)
-_
I
rt--l
Ir<11
24
If. lxl ¡ 1,
then,il-l
=
IJ [t"*r,* ln-"
¡tor,,,),,|',r"x &..¡*ttk)- ! s-t* - y)
snrp-,tU)dy]z= i1'1,o*o
;,f-"tt"*.,*)u Ls*p(x)-
const.e-Ml - r,,,)
ra(t,-tt>¡n-1
à fl
frogo:,,f -' (^r-::,)'þ*øl-- co'st r"(;)J
=
f em nta 4. If "þ I
n, and.peÐll+,
iloen,yE C
R,,1
(9) lg,,t,(g"*p)o-'(x)1t,-t sQtg"p,¡
2,nt,B>ßv@),2=/)<
co,p> l)_2,
I
(10)
lg"*(gn,* tù'-'(*)lo-rzQrgaþ,þ_2,,,,exy.(x), r <.þ <
2, p<þ _2:
iÍ þ :2,
the 'ineoualities(g)
anrt.(r0)
hotd./or^þ 2 0 ott4 p s 0,
rcsþccti- ucl!;
Q,., Q,{ 0' or, ,onitå,rx iìlilrìrclení'of i, : "
"Ilirst,
considerthe
case/ > 2; by Höid.r,.
iu.ecluality,(11)
Eox (Eo* r)*@):
Sgn(ø- y)l\g,(y --
z)d.¡t(z)lr:,
d1,:
-I l
: \9,(x-),) s\Ø!r),r,-",,,,s(x-y¡l\g*0-z)
gaþ_ t), t_z,n,s(x-y1a¡r"12¡1trd.ys
þ-1 _l
sl\gli
@-
y) s!-É,t,!,_2,,n,r.(x- y)¿ylilí l\sq¡_n,¡_z,n,s(x _ i)
.lyl 4 tu lvl> t
\s"U - z)
d.¡t(z)dylþ-' :
RELATIONS
:)
logo-1 þ-2
,fl-l
n
27
(r loge 15
I'tn
2. Tke
ca.se x+
cÐ8u
*
9dþ-t),þ-z,u',8(x) 2
Io:
g,(r - y) g"ø-u!)dy
¿,"r^:,,1u
lui,e,o{ò
- } r*tùlz l
Eaþ þ-2 ,,p(*),o8r, /ut
-
1þ-2
>n
,t: fl-11
as
desired.26 PETRU CARAMI\N 14
à
const. S.(e)n
(logu ä)o -"(ror,,i, )'
o-'
\ra(t-\ +at
etu 2I
coust. g.(p)Íi (t"r-;J'-' (t"*. å)u
po(þ-t¡ >il-1
à
const. e"p(p)^I [t"*^;)'' (,"*,ii)u ]
const' Boþ,þ-z,u',ç,(x)2. Tke
cq.se x->
co.Eu* SaU,- 1),þ-2,1il,s@)
> In
>tt. -l '"'
)
corrst.,!, (t'*^
,t,,,\n' (t.*,
i)ut"(3t,,,) I
t'u'(þ-t't-'dr
>('r,
-,);,,,0 '' (1og,,, )-,,,1u 8*{',,,)'r'þ-1) >colrs
¿
^l==l'
i;,,Y
I
const. tr-1fI
À.:1
logu
',to*"'
|,,1u
8"?"') à
const' suP'P z'n'ø(x)Thus
go* lloØ-tti,þ-,2,ilt,(r
(r) I
const. 8q!,,þ-2,,,,p(x) for
løl;
1,arrcl
this
cornpletesthe proof of oul
leruma'Urrder the^ more
restrictivc
coudition aþ{ tt,[
obtainedthe
follor'ving strongerresult
generalizing lernma3.2. ol
t). ÀDÀIISand x.
IIÐYDRS pa-per [2]
:I;emma 3. lÍ
"1,
Itø,
th'en&ab t\, þ'2,jil,þ'i' 8o : 8o *1 $'a(l> t), þ-t, m,9 - 8aþ,þ--2,u,í)'
Ott
accotttrtof the
lrreceding lerntna,tt'e
lta\teouly to
provethat
8n r,, 8oþ-t),þ,2, kt,g
(x) I
const.
gaþ,þ'-2, ilt,9(x)also
for 2<þ <
co.Usiug thê notation oI the
preceding lemtua,u'e
get7. Tlte
case x-,0.
8a'! 8nlþ-t),þ-",*,8
þt) > IL
>à
c:oust.'It][,"*, !^f-"(tus,,,llus.(3e)
\ratt-t)-r
dr:
r:1 \ P, \
o
t1l ,
:
Çonst.F, (t"*, i)o-'(tot,,, i')u o.'-" à
corrst. 9o.þ,þ-2,,,, B (P) àà
const. gnþ,p-2,*,s @).8qþ, þ,2,., p n',
¡r(r) :
5 Bzo(x - y) (ttu- o\)'on¡)
S grn x v@): :&*&*¡r(ru),
.rvhich completes
the proof ,of our
lenrma..RentarÌt" This is ari extension of lernma 3.s of D. ÀD^r,rs and N.
Irrry'Rs l2l. PropositianT, I"f ECR" is an ønølytic
set,therucø,p(E)
S
C.,¿(E) S?
õ,¿(¿).If uc
reþlnctir¡, Ityiå¿,
tl,ten, the abotte,irceqn,ality hotrlsfor
alt, sets E.TuEoRDlr ,3.
Let eþ {
n., then,(13)
B("þ,ù(D)SBrop,¡-r,*,øt(E)S?iB.,r(Ë) (2 <1 <q< a, IJ>þ _2), ,,
.Bo,p(E) S ?rBr.¡,,t,-2,.'pt(E)S0rAi.p,or(E) (t <q<1< 2,
þ<þ
__2) ;tt
*o!dlol g)0
anrtp ( 0,
re.s-t
ofE
ctnd tlte caþøcity Bìp,p_r,,,,gt measure for |top, r_. ,, ,,.ar(F),by the p'o""äiåg-'íä,ilá;
from the
preceding pro-llrrll, {
QrT,,p(F)sgrB,,p(F).
îhus
b(oþ, þ -r,,,,øt(F) S
?J,,¿(F) S
?rB.,p(F),lJìl;îîîji-,þ-2,ilt,8¡ is tr' i''er
capacitl,,and
Bn,,an
orrterca'acity, it
Bt"p,oíE)
S
Er*r,¿-r, .,Bt(E)is a
cli¡ect consequenceof the
relationri^ tno'o?) :
,-.: rlo 9cþ,þ-z,nt,g?)
,,uu"
.tn"
secondinequarity in this lemma may
be provedin a
similarfìË1,{rioNs
rnequality
29
the
Bkp,p-", *,pt(E)
=
bîop,p-2,.,st(E) S
?r8.,¿(E)ú
airdif p<0
28
But,
(t2)
Þ þ-r
-1\ d-' ø
ela? tt, þ -2,th, ø(y)dyr
0
¡ p-1 ilt-l Å:l
n
logu
PETRU CARAMÀN
r- I l-
n-'l ,:Qi<q¿
llos-..:
16
:
coilst. ,,for
p) þ --2 and
p(
r,,,.Next, lor R 1r,,,,
þ t -1
s!,-t b,) gþ"tp' ,t, þ--2,,n,g
til-l
(y)df,
S
cnost.fl
h:. I
- l)-ø(l'--l) F,'
þ-2 I log,,
I
1',
p--2 -9 dy
: (
const.r
f
0
æ
i (t'*-,-1rl-'
-Pæ (t"*,,
;,;
,*
\,
-2'ï rt'-2 dl'
Í
Q'"<
ø¡,heuce arrd.
takirrg iuto accorint (11), (12)
aucl lertrtna2,
$,e deduce (9), rvhere Q,: [rnax
(Q'r, QL))þ-'..A.trcl no$,, consid.er
the
casc 1<
'þ<
2, fuon
lernma2
anð' Hölder itrec¡ralitS',u,e
get8qþ,þ z,ru,gxlr.(x)
5
const' g,lþ-t),þ-2,,,,þ*8o+p(r) :
:
col1st, \Eotp-r¡,p t,^,çt(:v--
)ùgi-þ@ -- Ð el-'Ø -
l')ig*(J'-
z)d1t(z)d'yS1- þ t
I
const.fSST@ -- y)
g'rpL,t,þ-ù,ur,ø(*- y) dyl'-þ'
' {\
g"(x-
y) lg,'(y-
z)d'1t(z)10\'¡^'¡'-' :
1-þ 1 I
:
colrst.l\ s".-'u)
s?þþ ,r,p-r,,,,ø(y)dyl'-plg** (g,* P)'-' @)lþ-t, aud
arguirrdas
above,it
follorvsthat
1-þ 1
\ g'*-þ ( )') s?(þ!-t\, p -r,,,,
ø(i)
d'Y< *,
herce, we obtain
(10).F'inally, in the
case 1ó:2,
ott accouutof (3), if. p
2-0:
En*
go* v(tò: Bzo*p(r) :
g*p x F@)S
5g*p(ø- t)(log,,¡\,\'Ortrl -
: 8eþ, þ-2'ilt,9 * P(#)'
alg,* V)þ'',pl< 0p,, il tlogojìo, 0 (
pS
po,ultere
Q is ø
constønt indeþendentof p
ønel pois
sorffic,iently s*ø11,.Remarh.
'rhis corollary is a' exte'sion of
lemma 4.2ir
D. ADÁ.nrsand
N. MÞYEns'paper l2l.
Lemma 6. Let a{n qnd ), =L|;
swþþoseuhere s
>
1,9,
is _a co,nslant 'ineteþend,cnl. o.fp
ønd po ,issufficienlly
stu,oll.Then go x
)'
zsø
boomded. fuu,ctio7.t..Define
ll^u ::""1É ternr of the right part of (ra) is the convolutio' of a
boun-rrqq
'
function rvith a
,nealure ^o{ fi'it! total variation
a*d.is thus
arso,uqunded,
as
d.esired.31
.
Bn* r(s) : /,
,rì,(x) I
(5"- !*) *
x(x)1
f
1
r
,D- 1
Po
n
f
I
0
-
const-s
RELATIoNS
B(t,pu)
I
Po
ã"?):
{
const..llog* --
,Þ: I
t
h,ellß
log;
Þo
o8,,
logo -s
p p
Togo
1og,,
f
Po
Po
const
Eo@
- y)dt'(y) (
const.\,"-"
. e\a(),,x,r)
9n-l
,,-,t1,,, "
I==t,
{t"r,
-j )1o9,,
g"
x
),(x):
\ g"@-
1,)ct),(y):
f
:
const.fJ
-1,ìt _1
o<PSpo(1,
I l-'q
_-,l
ri;)' "'
g*(r) lor 0Sz(pu, 0 for r)
po.I{eu'rite
(14)
But
J-']
tù -l
u(1,
p) S 0rp"-"
À:tf]
,U,
(t.*-;lJ-'[,,r,, jt-"-
const. (1og,, tt_1<
const..
*[ [t'*, jl-'
[to*,,,
*)-". *
30
þnînuctn¡tMaN
18Remark.
this result improves theorem 1'
exceptfor the
case 1<
< þ < 2
andt"pt"r""îr- un-ät"osion of n.
ÀDAl\rS and, N. ¡ITIYERS' theo-t"ttt 3.3 io l2l.
-""
C*ofmry.ö"pE:0+ Bnt,-r,,,,g.(E):0
VP>.n-2 (nr':!'2' "')' iet
us"recafi
somenotations' For
[l,e ]ii +'
settt(çr,
x,
P):
B(r,p)I ,*trl
ror x =R',,0sp<co and
alsou(p,
p):,.:tt;,
a(p.,x,
p)'PropositionB.TetEçiR"bcaxl'ønal'1'l:icset'Ho(E)'0¡ÍÍ
th'eve exisîs
¡r e
&lL+, V.+0,
suck thatu(v,
p)Sl'a(P),0<PSPo'
:(For
.a proof,
see L. cÂIìT,ESoN[8],
chap,II'
theorerrl1' p'
7')Ärgurng as 1n D.
^ooiî'ä"ïi". *tnieo*' itttt*" 4'1 of [2']' we obtai.
LË;; a 5. L,et,i?-71 o*A
Àe'5ìL+;
suþþosetkat\9' 0< p
Swhere
Q is
'ind'eþend,entof
P.IIence, for
d1:
tt'- eþ, so: Qp- l, (h: l'
'"'
ttt')dz- tu
arló'to:O (ø:7, ,.., b), we obtain
theCorollary. Let uþ {n
ønd' ¡t.=LI;
suþþose thcrtu(p, p)
S 0,p"-'r' ,U [a*, l)'-'r, 0 <
P(
Po(
1'tuhere
Q, is ø
conslømt ind'eþend'entoÍ
p'u(P, P) S
0rPo'il
anrj
a
v.)
[t"*,+)-",0(p(po,
['or, i r-'*
Spo(1,
i)-'-]"0-É
u(À, p) S
0,p', -LIlt"r,;)-u,
, are
cotcstants 'índeþen'd'en'tof
9'l,
zae kau,u[(g*
* p)'
À,p] S
?[e.-"*n'rU,(t"*,
wkere O
S¿lt(n-ad'r{n
Then,,
for
0<u < *"*
l.f ,
ønd' Qt,
do - (tt' - (n - a) -- cl,
ùi iEi^AiioNs
å3flew
iin the case
l:<,þ <2.
'I1histhçorem
gerreralizes theotem4.3
ofD. ,{DArrs anc1. N. ìIDYERS
l2l.
Corollary. CapE : 0 +'
H,0,,,r,,,(r(li): 0
VP>
!1'- |
(rtt': l, z,
. ..),
wh,ere h,,-t,,,.s(t'):'i1i (to*-
)
)'-
" 1,o*,,'
1-u
This is a
corlseqLrenceof the
precpding thcorenrand of the
corollafyof
proposition4. But it na1'
be obtainecl also ftomProposition 9. CapE:0+Ho@):0 for a'll
tneast'wefttnc-tdonsh søtdsfydng ,
,for
0< r¡ 1L safficicntly
smsll:'
',For,the
,proof,,see
rr. .tr,¡rrr,rN (.l2ql,, ,theo¡ern4.1)
or.,D.
,,\pAlIÍ$([1],
theorern2).
:' ,In order to show that thc
precedipgtheoren is.best
possible, we recall some definitions ancl previous results.Propositio'n 10. Let:h,'be a
inecisørefunction
sutisfyinglet us
søyfor 0Sz(J.arrrl -2
zalnrc0<?<"ç. If
I'-i.srtCnntot'sel 'in R,
lken(Ilor the proof,
see D, ÀDr\ìrs ancl'N.ìlJr'lr{s [2], proposition
5.1.)A set
ËC R" is
saiclto have a
|,otuer sþheri,cnl h.-densityat a
þoittl11,,,
IrirtlzlJl4
_-, o.,.-n
h(2ri.-,'irP
r
op
ll.'l'Jt¿: sct E lt.os,l,ozqtzrsþltar
il1, ¡¡¡Vx =
E,u4e/.c.E.is sutl'tcienll! ct
kol.ds, satisfl,irt,g tø:h,cre tlte.0< H;,(E)<
citttstantQ 0<r {rr(r,
'<0 <
2', and,{'\r,s; ø:
scl tyþtt E = ), 8,,,
willt,,fì,,,, n.,llte
rtitt, slt:þ,'n-d.itnensionnl
"irìrrrnls,
zadth,eclges
pf
leu,gttt, 1,,,, 2lu,.i.r1
n,
th,e u5unl,'øøy
snlisJl,i¡1g llre foll,ozuin,g tlou,ble inequ'a-iir i
.c| 12"h(l,n) I ,r, ci!
cz col?,st&tlts.3 -- L'aualyse numérique et la tbéotie de l'approximation
- Tome ? - No. 1/19?E
lim
,*7o_l a
(16)
1
'h,(zr)
{
Qh(r),(15) ''
!r,
çorusistinp of ,,,)',u ,.!',1,,,, oitaínert ¿
tdty
B2
þsrnu c'A'itrtiu'dÑRemørk. This is an extension of lemma
4'3N.
-
MEVERS [2].ìiieo*dr a. Let uþ { n'
ThetoHn
l
Hnoo,p-t,rr,91 Bn,¡ ,zahere
h(r):/t!-aÞ(t"*il'-o Ío' q>þ ønd'r<L' and'whcre
\h,ns,p-t,n,,B(r)
: ,.-"0"#r(t"r- i)' -' (t"*' i l-u
(m: r' 2'
' ' ')Vp > þ - 1
and' 0<r <r,,, with'
1og,,, -1-7
1'First, 1et E' be an analytic set ''i;i'lt
Ho*o,t-t,'',p(E')> 0;
then'frorn the
preceding proposition,there exists rr+-ö'sui1t't1rat
¡.r.= 9ìL+(E)ancl
We niay
asstlmethat
¡-r, hasa
compactsupport'
Then',by the
preced'ing;;;il"ú,
rvhereo-îi ô:i,-"''' t* lj'anci Ç")þ' it
foilowsthat' takingì:(g"*p)p_',weafeinthelr¡,potlresesoftlreprecedirrglemrrra, which
aliowsus to
concluclethat
go*
(g"*
p)'o-tis
bounded-i'
R"by
arò-l
constant ln 1æ. But
sinceoir,,+ 0
anclt.[*'* #=) (ø) s f it
B",p(E)
2 0,
hence Hh,þ,þ:t,n,,p1 Bo,p,as
desired''rhe inclusion Hîä-ii';:;,þ-1,u,,þ Is a direct
consequenceof
the relationRe,tørþ.
The
assertionof this theorem for þ >
?.is a direct
con-' sequenceof
proposîiior,-O
no.l tf,"or"ä-ã,
ftotuå"átits contribution
is- 0 for q>
þ.1
'r
i
r 1ogo,
r+0lirn
("'i)'-'
20
of o. ¡o¡rrls
and(rn:1,'2,'..)
m-l a(v,