Appl .Mat h.J.Chi ne s eUni v.Se r .B 2005,20(3):352362 ON THEORDER OFAPPROXI MATI ON BY PERI ODI C NEURALNETWORKSBASED ON SCATTERED NODES ZhouGua nz he n .Ther Abs t r ac t e l a t i ons hi pbe t we e nt heor de rofa ppr oxi ma t i onbyne ur a lne t wor kba s e don s c a t t e r e dt hr e s hol dva l uenode sa ndt hene ur onsi nvol ve di nas i ngl ehi dde nl a ye ri si nve s t i ga t e d. Ther e s ul t sobt a i ne ds how t ha tt hede gr e eofa ppr oxi ma t i onbyt hepe r i odi cne ur a lne t wor kwi t h onehi dde nl a ye ra nd s c a t t e r e dt hr e s hol d va l uenode si si nc r e a s e d wi t ht hei nc r e a s eoft he numbe rofne ur onshi di nhi dde nl a ye ra ndt hes moot hne s sofe xc i t a t i onf unc t i on. () I *t r +,-c t . +* / nr e c e ntye ar st he r ehasbe e ngr owi ngi nt e r e s ti nt hepr obl e m ofne ur alne t wor kand r e l at e d appr oxi mat i on,many i mpor t antr e s ul t sar e obt ai ne d.0e c aus e ofi t s abi l i t y of par al l e lc omput at i on i nl ar ges c al eand ofpe r f e c ts e l f adapt i ng and appr oxi mat i on,t he ne ur alne t wor khasbe e nwi de l yappl i e d.Theappr oxi mat i onabi l i t yoft hene ur alne t wor k s (3)i tR beans di me ns i onalEuc l i dSpac eand2 sa de pe ndsoni t st opol ogi c als t r uc t ur e.1e s s r e alf unc t i onde f i ne donR .Whe n2(3)i sane xc i t at i onf unc t i onand34 R i sani nput ,t ve c t or hes i mpl ene ur alne t wor koft hr e el aye r s(onei shi dde n)andnne ur onshast he n s s (8639 : .;e f or m 5 a62 r et hewe i ght i ngve c t orc oe f f i c i e nt864R ,node s: nda6 6) 64R a 67 1 . ar eal lr e al s s s <1,=>R s Fori nt e ge rs howst hes e tofs di me ns i onalve c t or swhos ec oor di nat e sar e s F E G s .? 7 @A B,BC 7 @AB,BCD@AB,BCD...D@AB,BC.Hp e not e st hate ve r y i nt e ge r s ? d s s var i abl ei ni thast hepe r i odof2Bandi ti sane ne r gys pac eofs di me ns i onal1e be s gue me as ur abl ef unc t i ons(1I pJ 9 K,L37 L31L32...L3s)whi c hs at i s f yt hef ol l owi ng e qual i t y: 1214. Re c e i ve d:2004MR Subj e c tCl a s s i f i c a t i on:68W25,68T15. :pe Ke ywor ds r i odi cne ur a lne t wor k,or de rofa ppr oxi ma t i on,J a c ks oni ne qua l i t y. Suppor t e d byt heFounda t i on ofZhe j i a ngEduc a t i on Commi t t e e(20030431,20030631)a nd Doc t or Founda t i onofNi ngboc i t y(2004A620017). Z|o uGuawz|e w sERI tDI CNEURALNETWtRKS ‖f‖ * p,s= 1 |f(x)|pdx (2π)s Qs ( ∫ 353 1 p ) <+ ∞. ∞ LQs de not e sane ne r gys pac ewhi c hc ons i s t sofc ont i nuousf unc t i onst hathavepe r i odof2π f ore ve r yvar i abl e,andwewr i t e ‖f‖ * x |f(x)|. ∞ ,s= ma s x∈ Q s 1 ∈Z,t : Forl hemul t i Four i e rt r ans f or m off unc t i onf∈LQs i sde f i ne dasf ol l ows 1 -i l x f(x)e dx. (2π)s Qs ^ f (l )= * ∫ d * p ≥d≥ 1(s ,d∈Z)andφ :Q →R whi Le ts c hs at i s f i e sφ ∈LQd.J=Jd,sbet hec l as sof .I al ld× sr e almat r i c e swhos er anki sd ande l e me nt sar ei nt e ge r s n[1],Mhas karand )≠ 0,l∈ Zs,t Mi c c he l l ipr ove dt hatwhe n^ φ(l hef i ni t el i ne arc ombi nat i on ofne t wor k s t r uc t ur e * Δφ* ,J(x)= {φ (Ax+ t ):A∈ J,t∈ Qd}∪ {1}, p ,Span(Δ* x))c anr e al i z et heuni f or m appr oxi mat i onf orf unc t i onsi nLQs.Thust he t hati s φ ,J( ne ur alne t wor kope r at or sc anbec ons t r uc t e dbyme ansofdel aVal l r esous s i ns um of . Four i e rs e r i e s [2] tn t he ot he rs i de,u ac ks on The or e m i si mpor t ant t ot he appr oxi mat i on of : t r i gonome t r i cpol ynomi nal sandal ge br ai cpol ynomi nal sasf ol l ows 1 f)p,1 x yz{ f, v* w( w ( ) ,f∈ L ,1x px+ ∞, p1 Q (1) p,1 whe r e z{(f,t )p,1 = s up‖Δ| f,x)‖ * {( p,1, 0< |x t { Δ| f,x)= {( ~ =0 { () { -~ } (- 1) ~ f(x+ ~ |), * v* f)p,1 = i nf‖f- t w‖ p,1, w( t w∈ Hw Hw i st hes e toft r i gonome t r i cpol ynomi al swhos eor de ri sl e s st hanore qualt ow. I ne qual i t y (1) s hows t he r e l at i ons hi p be t we e nt he or de r of appr oxi mat i on by p t r i gonome t r i cpol ynomi nal sofwor de rappr oxi mat i ngf unc t i onsi nLQ1 andt heor de rwof ({ ) p .I t r i gonome t r i cpol ynomi nal s fwes uppos ef (x)∈LQ1 i n(1),t he r ee xi s t sac ons t anty> 0whi c hs at i s f i e s v* f)p,1 x w( y‖f({)‖ * p,1 . w{ (2) Thi ss howst hatwhe nt hes moot hne s sofobj e c t i vef unc t i onshasi nc r e as e dandt heor de rof t r i gonome t r i c pol ynomi nal s has r i s e n,t he or de r of appr oxi mat i on by t r i gonome t r i c pol ynomi nal sofappr oxi mat i ngf unc t i onsc anbear bi t r ar yr ai s e d.Byme ansofmul t i var i ant ,ape t r i gonomi t r i cpol ynomi nal s r i odi cne ur alne t wor ki sc ons t r uc t e dandt heappr oxi ma- t i onor de rc anbee xpr e s s e dbys e c ondmodul usi n[3],t he nt heappr oxi mat i onde gr e ec an .Mat .B h.J.Ch} ne s eUn} v.xe r Appl z54 .20,No.z Vol 1 (n).[4,5]haveconstructedakindofneuralnetworksbyusing Bernstein 1 ,butt Pol ynomi nal s heappr oxi mat i on or de ri sonl yO (n). Doesthereexistcommon ge tt oO J ac ks ont ypet he or e m aboutpe r odi cne ur alne t wor kappr oxi mat i onl i ke(1)? I nt hi spape rwei nve s t i gat et hi sque s t i on.Ther e s ul t sobt ai ne ds how t hati ft he e xc i t at i onf unc t i oni ss moot he nough,t he nt hede gr e eofappr oxi mat i onbyt hepe r i odi c ne ur alne t wor kwi t honehi dde nl aye rands c at t e r e dt hr e s hol dval uenode si si nc r e as e dwi t h . t hei nc r e as eoft henumbe rofne ur onshi di nonehi dde nl aye r I nt hef ol l owi ng,wel e tC,C(r),M(r)bec ons t ant swhi c har ei r r e l e vantt of,n,but .A=O(B)s t he yar er e l ave ntt ol e t t e r si nt hebr ac ke t howst hatt he r ee xi s t sac ons t antC> α ≤C2.Forx, β s y∈R ,weus ex≤yt ode not et hatt hec oor di nat e sofxi snotbi gge rt hant hec or r e s pondi ng 0whi c hs at i s f yC1≤ c hs at i s f i e sA≤CB.α~βde not e st hatC1>0,C2>0whi . c oor di nat e sofyi nt hef ol l owi ngs t at e me nt bc defgh g ffij m ke tl beanor me dl i ne ars pac e.Thec l as sl i st hec l as sofal lc ont i nuousl i ne ar f unc t i onal sonl wi t ht henor m nxm n lm o = s uppqxm (x)qonxn l ≤ 1r. [u] ,andl sg ffit. vuppos el,w ar enor me dl i ne ars pac e s e txo wy l beac ont i nuous ,t l i ne arope r at orwhi c hi sbounde dbe l ow,t hati s he r ee xi s t sapos i t i venumbe rA s uc ht hat nyn w ≤ Anx(y)n l,f oral ly∈ w. m m m (z) m I fy ∈w ,t he nt he r ee xi s t sx ∈l s uc ht hat oral ly∈ w, xm (x(y))= ym (y),f (4) and nxm n lm ≤ Anym n {m . ~ (5) (~) | ~ =(| ...,| ,...,| ∈ Z ,θ = (θ ...,θ ,...,θ ∈ [- π,π](0≤ | ke t| | θ 1, 2, } ~) | 1, | 2, | } | ~) }≤ ~ (} ) =1,2,...,~)beadi qand n,} vi s i onof[- π,π].Fur t he r mor e,ke tδ = max qθ | + 1- θ | } } 0≤ | ≤ n- 1 } (} ) t hebi gge s tpe r t ur bat i onδ= maxδ .The nwehavet heGaus si nt e gr alf or mul aandt he 1≤ } ≤~ . Mar c i nki e wi c z Zygmundi ne qual i t ybas e dons c at t e r e ddat aasf ol l ows (~,n) sg ffic.The r ee xi s tw| (n) (n) (n) =(w| ,w| ,...,w| )∈R~(0≤| ≤n)and0<η≤ + ∞ whi c h 1 2 ~ η ~ ~ ,t he nf orar bi t r ar yt Hn i st hes e toft r i gonome t r i cpol ynomi al swhos e n∈Hn( n )t or de ri sl e s st hanore qualt onandwhi c hhave~e l e me nt s he r ee xi s tc e r t ai nc ons t ant sC1 s at i s f i e sδ< >0,C2>0s uc ht hat m C1nt nn p,~ ≤ 1 (~) qt θ qp n( | ) n~0Σ ≤| ≤n ( 1 p ) ,1≤ p≤+ ∞. (u) PERc yDc CZEURA|ZEkmyRKS Zho {G{anzhe n ~55 Fur t he r mor e,f orar bi t r ar yp>0wehave 1 (k) |t θ |p n( j ) nk0Σ ≤j ≤n ( 1 p ) ≤ C ‖t‖ 2 n * p,k , andt heGaus s t ypef or mul a 1 (2π)k ∫ t(θ )dθ= kn [- π,π] 1 (k,n) (k) wj t θ , n( j ) nk0Σ ≤j ≤n (7) k (k,n) whe r ewj (n) = Twj ,0≤ j≤ n,s at i s f i e s U U =1 1 (k,n) V |wj | nk0Σ ≤j ≤n ( 1 V 1 1 ) WX Y,p X V = 1, andt heZi [ol s [i ii ne \ual i t y 1 1 k (p^- p ) ‖]‖ * n ‖]‖ * ]_ ‘k 1≤ p,p^WX Ya p,k ≤ C p^ ,k, n, (b) a c ne \ual i t y(b)i sd al l e dt heZi [ol s [i i t ypei ne \ual i t yoft r i eonomi t r i dpol ynomi nal a(7)d fg hhi ome sf r om [7,b]and(b)f r om [j]akhe nweonl yne e dt opr ove(l)a q k * (k) (k) r0≤ j≤ ns‖qt r‖ p= θ θ mr i t en=‘n,‖o‖ n=‖o‖ p,k,p= qt n( n( j ) j ) 1 (n Σ k 0≤ j ≤n (k) t θ n( j ) 1 p ) WXY ra p (k,n) * * (n) (n) (n) r_uk and Fort _p = qqwj r=qwj1 ,wj2 ,aaa,wj k ‖t* ‖ p* = 1 (k,n) wj nk0Σ ≤j ≤n ( 1 V V ) WX Y r, k v wede f i net hel i ne arf unt i onalon‘n asf ol l ows t* (t n)= 1 (k,n) (k) wj t θ a n( j ) nk0Σ ≤j ≤n (j) khed ont i nuousl i ne arope r at orwsnxp i sde f i ne dby (k) w(t t θ r0≤ j≤ n,t n)= q n( n _ na j ) (10) khe nby(l)wehave ‖t n‖ n ≤ 1 ‖w(t ‖ p,t n) n _ na C1 (11) ybvi ous l y,t hef und t i onal z* st nx 1 (2π)k ∫ t({)d{ kn [- π,π] (12) * * * * s at i s f i e sz _ n and‖ z ‖ n* W X YaFr om |e mma1we[now t hatt he r ee }i s t st = (k,n) qwj r_p* s at i e s yi ne(7),and ‖t* ‖ p* ≤ 1 ‖z* ‖ n* WX Y, C1 t hati s 1 (k,n) V |wj | nk0Σ ≤j ≤n ( 1 V ) WX Ya >0,t Fori nt e ee rr heee ne r al i z e dJ ad [s on[e r ne li sde f i nde dby (1~) .Mat .B Appl h.J.Chi ne s eUni v.Se r 356 n r t s i n 2 = s i n 1+ .20,No.3 Vol t)2r 2 , ( [ ]) -1 kn,r(t )= λ n,r = ) whe r e[x]+1de not e st hes mal l e s ti nt e ge rt hate xc e e dsx.Le t 1 π kn,r(t )dt , 2π - π ∫ λ n,r = 2r -1 by[10]wehaveλ n,r~n and π ∫tk (t)dt~ n ,1≤ k≤ 2r- 2. k -k n,r -π I nvi e w of[11],wege t t)2r 2 n r t s i n 2 = s i n 1+ ( [ ]) = ( = Σ n) i kt β( |k|,re , n k= - r r [] ) n [r])aregivenby (n) whe r eβk,r 0≤k≤r n [r] r r -1 n) β( 0,r = j =0 = 2r (r- j ) 1+ j n ) ( [r])+ r- 1 ; () Σ (- 1)j = 2r- 1 ) n = ) = r- 1 2r (r- j ) 1+ - k+ r- 1 j r ( 1 ) ,1≤ k≤ Σ j j =0 = 2r- 1 ) () r -2 = 2r (r- j ) 1+ () j Σ (- 1) j j =0 ( [ ]) n n [r]- (r- 1); ) ( [r])- k+ r- 1 , = 2r- 1 ) n n [r]- (r- 1)+ 1≤ k≤ 2[r]- (r- 1)+ 1; (n) ........................................... βk ,r = <. = r 1+ n ) = = 2r- 1 ) = n ) ( [r])- k+ r- 1 - (21r) (r- 1)(1+ [r])- k+ r- 1 , n 2r- 1 ) n [r]- 1≤ k≤ (r- 1)[r]- 1; = n ) r 1+ - k+ r- 1 n n [ ] r ( ) ,(r- 1) [r]≤ k≤ r[r]. (r- 2) == 2r- 1 ) s ∈ Q ,wede )= kn,r(t ...kn,r(t Fort f i nemul t i ke r ne lf unc t i onKn,r(t kn,r(t nd 1) 2) s)a ge ne r at e dJ ac ks onme an Jn(f,x): = Jn,r(f,x)= r 1 (- 1)j f(x+ j t )Kn,r(t )dt . s s Σ (2π) Q 1≤ j≤ r,j∈ Zs j ∫ =(j ...,j )asf : Al s owedi f i nej j ol l ows 1, 2, s () (14) PERI ODI CNEURALNETWORK{ Zho uGuanzhe n s j t= r i =1 r r j 1 j 2 r () ( )( ) ( ) Σ jt, j = ii 357 ... j s , (- 1)j = (- 1)j1(- 1)j2...(- 1)js. ,wec Thus ange tt hef ol l owi ngLe mma. [9] p ≥1,f∈LQs,1≤p≤+∞,t )>0s he r ei sac ons t antC(r at i s f yi ng Le mma3. Forr 1 ‖f- Jn,r(f)‖ * (r )wr f, p,s≤ C n ( ) s ,f∈ Lp Q, (15) s p,Q whe r e wr(f,t )p,Q = (∫ s up s wr(f,t )∞ ,Q = Q ) h r ,xi s up ‖Δ (f,x)‖ s 1≤ i ≤ k,0< h≤ t r Δh f,x)= r ,xi( s 1≤ i ≤ k,0< h≤ t 1 p p Δh f,x) dx ,1≤ p<+ ∞, r ,xi( l =0 r ,p=+ ∞, () r -l Σ (- 1) * ∞ ,s l f(x1,x2,...,xi- 1,xi+ l h,xi+ 1,...,xs). Fr om (14)wege t Jn,r(f,x)= r () 1 Σ (- 1) j (2π)∫K j 1≤ j ≤r r () s 1 Σ (- 1) j (2π)∫K j 1≤ j ≤r s (t )f(x+ j t )dt= n,r s Q x (u- j)f(ju)du= n,r s Q r () j 1 Σ (- 1) j (2π) × 1≤ j ≤r ∫[ [ ]Σ x s Q -r s n n ≤ k≤ r r r - s (n) i k uλ n,rβ |k|,re( j) ]f(ju)du= [] r () [ ]Σ [ ] j Σ (- 1) j 1≤ j ≤r - s (n) λ n,rβ |k|,r × n n -r ≤ k≤ r r r kx 1 - i i ku (j u)e du e j , s sf Q (2π) ( ∫ ) s klxl kx =(j ...,j ),andde . f ork=(k1,k2,...,ks),j j f i neβ =β β ...β , = Σ 1, 2, s l = 1 j j l 2i I nvi e w oft heLe mma3.3n[10]ort heLe mma3.2i n[12],wehavet hati ft he r e (n) |k| (n) (n) |k1| |k2| (n) |ks| 1 s i ku f(j u)e du= 0.The doe s n' te xi s tα∈Z s uc ht hatk=j α,t he n r e f or e,t hi sf or mul a (2π)s Qs ,he i sane ve nt r i gonome r i cpol ynomi nalofor de r≤nandhasse l e me nt s nc e y z i kx Jn,r(f,x)= Σ Jn,r(f)(k)e . ∫ - n≤ k≤ n {o Jn,r(f,|lx- })= Σ - n≤ k≤ n y z i k(|l x- }) Jn,r(f)(k)e = Σ y z i k|l x- i k}. Jn,r(f)(k)e - n≤ k≤ n ︵ [1] * p * p * )≠0,l ∈Zs. Le mma~. Le tφ ∈LQs,t he n{panΔφ i sde ns ei nLQs i fandonl yi fφ (l ︵ * p * )≠ 0,l ∈ Zs andni Le mma5.Le tφ ∈ LQs,1≤ p≤ + ∞.I fφ (l sl ar gee nough,t he nwe 2<=v 2B r--2 >2J2Q>? n] P ]@n? 92A] @ Fc; 2Y/0DJ2F CJL have * * + Jn(φ ,(-,. /0/1 -1 n2 * * + 27 34 556 89 he : e; <a-=h; > h< a9 ; < 8 ; e </1-1n< ?> h9 ha9Jn0@(φ ,(-,A /2BCDe EEaFaGH K 9 heIJ L He :; Ge M?aL ; 9 C0=ehave S * * * NJn0@(φ ,O φ N* R@ φ 0 -0P1 Q n T U 0 P -0V aGH X X X * * * (-,WA Wφ (-,O Jn0@ φ (-,WA Wφ S * * ; -\ Tφ (\,O Jn0@(φ 0\,U] H\ 1 (YZ,P VP [ S * * * QNφ O Jn0@(φ ,N * R@ φ 0 -0P1 Q n T U P ^ /0(n^_ ‘,2 -0V X * 0φ (-,A/0=h; 2 ah?< > h; EbL ; e <9 ha9De EEachJL H< iSj o o de ffgh2 De 9k(l,mn ^n peaG; G9 e q: apL e8 ?G> 9 ; JGJGV aGHa8 ?G> 9 ; JGJ8YZbe : ; JH J8e ve : Cva: ; apL e0rsJot P09 he G=ehave S S k(rv ,HvA (Yu,P VP (Yu,o [ [k(v,Hv2 o V wx ygz {4 e | }~ t ’ o * 8< baG)φ* 0J(l,; <He G< e; G*VP0pCiSj=ehave W: ; 9 e#φ* A$%s& mφ (%,./(27 - &P+$/(, $r %m%s # * φ 0rs J(2 (S., P 2Whe GoA PaGH#φ* / & +$/(0=eL e 9J pea ah; <: e < ?L 9> JG9 a; G<9 =J; EbJ: 9 aG9> a< e < 2ah?< 0)φ* 0J (l, > JG< ; < 9 <J89 he < ; GqL ebJ; G9< e 9=h; > h; <> JEbJ< e H J8?G; 9Ea9 : ; 0e < * 9 : aG< L a9 ; JGJ8φ 27 G9 h; <> a< e0=e> aL L)φ* 0J(l,9 he9 : aG< L a9 ; JGGe 9 =J: 1< 9 : ?> 9 ?: e27 GJ9 he : - P * s & +$/((2De > a< e0=he GoA SaGH#φ* / $S(0=e=: ; 9 eJA $2 m 2 9φ peaGe 0> ; 9 a9 ; JG 8 ?G> 9 ; JG09 he G3baG)φ* 0J(l,; <aGe ?: aLGe 9 =J: 1J?9 b?9J89 h: e eL aCe : <=; 9 hJGeh; HHe G 2 L aCe : P 7 9; <Jpv; J?<9 ha99 he : e; <JGe> JJ: H; Ga9 eJ8ve > 9 J:%s & =hJ< eap< JL ?9 evaL ?e; < P s&+$/(0=e> 0aGH=e=: p; qqe < 9 ; 9 e; 9a<N%N24J:2 hJJ< e%2s #φ* aGHr2sJ< ?> h9 ha9 - 2A r2 %20 (S5, =he : eN%2N ; <9 heE; G; E?E aEJGqaL L%2< a9 ; < 8 C; Gq(S5,24J:aGC; G9 e : qe :n6S0=e=: ; 9 e 7nm A Ea0$N%2Nm O n1 21 n02. /(2 - P s&+$/(0=eJp9 Ar2 %28 4J:a: p; 9 : a: C2 a; G2 : JE (S5,24J:aGCbJ< ; 9 ; ve; G9 e qe : <86Y aGH767n0=ehave S (YZ,o [J o V * ; %2 9 (φ 0r2lO 9,] H9A 708 S (YZ,o [: o X * ; %(r2 lO 9, ; J708 (φ ,(%,] ]%29H9A V O 71 %1 7 PERI ODI CuEURALuETWORKS oyz {|{}n~ye n Σ ︵ 1 * JN,α (φ )(k) (2π)d ∫e - N≤ k≤ N xw9 i (kl- k)v i kAl x dve = d Q ︵ ︵ * i kl Al x * i l x JN,α (φ )(kl)e = JN,α (φ )(kl)e . Thus i l x = e 1 ︵ * JN,α (φ )(kl)(2π)d ∫J * i kl v (φ ,Alx- v)e dv. (18) N,α d Q * i k· d d I nvi e w ofJN,α(φ ,Alx-·)el ∈HN+ |kl|⊂HN+ Nn andLe mma2,wege t i l x e = 1 ︵ * )(kl)(2π)d JN,α (φ ∫J d Q * i kl v (φ ,Alx- v)e dv= N,α (d,N+ Nn) wβ 1 Σ ︵ nd * JN,α (φ )(kl)0≤ β≤ N+ Nn (d,N+ Nn) * (d,N+ Nn) i JN,α(φ ,Alx- θ )eklθβ β . So Jn,r(f,x)= ︵ Jn,r (f)(l ) × ︵ * - n≤ l ≤n JN,α (φ )(kl) Σ d,N+ Nn) (d,N+ Nn) w( β * (d,N+ Nn) i JN,α(φ ,Alx- θ )eklθβ = β d n 0≤ β≤ N+ Nn Σ ︵ (d,N+ Nn) wβ Jn,r (f)(l ) iklθ(βd,N+ Nn) e × d Σ Σ ︵ n * 0≤ β≤ N+ Nn - n≤ l ≤n JN,α (φ )(kl) * (d,N+ Nn) JN,α(φ ,Alx- θ ). β (19) : Fr om (19)wec ande f i nene t wor kope r at orasf ol l ows * φ ,N f,x)= Jn ,r ( ︵ (d,N+ Nn) = Jn,r (f)(l ) iklθ(βd,N+ Nn) wβ e × Σ d Σ ︵ * n =- n≤ l≤ n JN,α (φ )(kl) 0≤ β≤ N+ Nn * (d,N+ Nn) φ (Alx- θ )). β (20) Thenumbe roft hene ur onsi nvol ve di nas i ngl ehi dde nl aye ri s * φ ,N ne ut r ons (Jn (N + Nn)dns). ,r )= O( q * ∈ I nt hene ur alne t wor kc as e,d=1.Wehavemφ* =nk∈opφ (k)r0s,Nn=1,Al=l s 1 : o,kl=1,β∈o ,he nc ewege tt hene ur alne t wor kope r at or sasf ol l ows * φ ,N Nn f,x)= ,r ( (1,N+ 1) wβ 1 Σ ︵ n * 0≤ β≤ N+ 1 JN,α (φ )(1) tΣ ︵ Jn,r (f)(l )× - n≤ l ≤n (1,N+ 1) * (1,N+ 1) i θ φ (l x- θ β )eβ . (21) uow,t henumbe roft hene ur onsi nvol ve di nas i ngl ehi dde nl aye ri s * φ ne ur ons (Nn Nns). ,r)= O( s ,Nn=n,Ali ∈o.Thus ,t I nt het r ans l at i onne t wor kc as e,d=s sauni tmat r i v,kl=l he : t r ans l at i onne t wor kope r at or sar easf ol l ows .Mat .B Appl h.J.Chi ne s eUni v.Se r 360 * φ ,N n,r M .20,No.3 Vol ︵ (s ,N+ n) = Jn,r (f)(l ) ilθ(βs,N+ n)) wβ e Σ (f,x)= Σ × s ︵ * n =- n≤ l≤ n JN,α (φ 0≤ β≤ N+ n )(l ) ) * (s ,N+ n) φ (x- θ ). β (22) Now,t henumbe roft hene ur onsi nvol ve di nas i ngl ehi dde nl aye ri s * φ t r ans (Mn (N + n)s). ,r)= O( ≥ d≥ 1,α≥ r≥ 2,n≥ 1,N> Nn,andal .Le The or e m 1.Le ts loft he m ar ei nt e ge r s tδ≤ ^* η * p s ,1≤p≤+∞,f∈Lp )≠0(l ∈Zd).I andφ ∈LQd s at i s f i e sφ (l fN i sbi ge nough, Q, N+Nn t he nt he r ee xi s t sac ons t antC>0whi c hs at i s f i e s └ * φ ,N 1 ‖f(x)- Jn f,x)‖ * ,r ( p,s≤ C wr f, n L 1 * nγwα φ , N + s M* p,Q n ( ( ) ) ┐ , (23) ‖f‖ ┘ d p,Q * p,s ^* * n ≤n},γ=s /mi whe r eM =mi n{|φ (kl)|:-n≤l n(p,2). kc as e,whe nN i sbi ge nough,wehave I nt hene ur alne t wor * 1 φ ,N , ‖f(x)- Nn f,x)‖ * ,r ( p,s≤ C wr f n [( ) s p,Q 1 * + nγwα φ , N ( ) ‖f‖ * 24) p,s . ( ] 1 p,Q I nt het r ans l at i onne t wor kc as e,whe nN i sbi ge nough,wehave └ * φ ,N 1 ‖f(x)- Mn f,x)‖ * ,r ( p,s≤ C wr f, n L 1 ┐ * nγwα φ , N p,Qs . (25) * + ‖f‖ p,s ^ s p,Q ┘ mi n φ* (l ) ( ) ( ) - n≤ l ≤n .Fr Pr oof om (19)wehave * N,α(φ ) Jn,r(f,x)= JJ (f,x). n,r (26) Soweus et heLe mma3t oobt ai n * φ ,N ‖Jn,r(f,x)- Jn f,x)‖ * ,r ( p,s≤ ︵ (d,N+ Nn) = Jn,r (f)(l ) ) |wβ | × d Σ Σ ︵ * n 0≤ β≤ N+ Nn =- n≤ l≤ n JN,α (φ )(kl) ) * (d,N+ Nn) * (d,N+ Nn) ,Alx- θ ‖Jn,r(φ ‖* β p,s≤ )- φ (Alx- θβ C(α) Σ 0≤ β≤ N+ Nn ︵ d,N+ Nn) = Jn,r (f)(l ) ) w( 1 β * wα φ , Σ ︵ * N nd =- n≤ l≤ n JN,α (φ )(kl) ) ( 1 * C(α)wα φ , N m* n,N ( * n,N whe r em ) d p,Q Σ ) d ≤ p,Q ︵ Jn,r (f)(l ), - n≤ l ≤n ︵ * =mi ≤n}.Us n{|JN,α(φ )(kl)|:-n≤l i ngt heCauc hySc hwar t zi ne qual i t yand t hePar s e vale qual i t y,wehave Σ - n≤ l ≤n 1 s s ︵ ︵ Jn,r (f)(l ) ≤ Cn2( Σ |Jn,r (f)(l )|2)2 = Cn2‖Jn,r(f)‖ * . 2,s - n≤ l ≤n Byt heNi kol s ki i t ypei ne qual i t ywede duc e PERI ODI CNE^RA_NEvWORKS Zho uGumnzhe n 1 1 1 361 1 ‖Jn,r(f)‖ * ns(p- 2)‖Jn,r(f)‖ * ns(p- 2)‖f‖ * . 2,s≤ C p,s≤ C p,s /mi Wr i t i ngγ=s n(p,2),wehave ︵ Jn,r (f)(l ) ≤ Cnγ‖f‖ * , p,s Σ - n≤ l ≤n t he n 1 * , C(α)nγwα φ N φ ,N ‖Jn,r(f,x)- Jn f,x)‖ * ,r ( p,s≤ m* n,N ( * ) d p,Q ‖f‖ * . p,s So * * φ ,N φ ,N ‖Jn f,x)- f(x)‖ * f,x)- Jn,r(f,x)‖ * f,x)- f(x)‖ * ,r ( p,s≤ ‖J n,r ( p,s+ ‖J n,r( p,s≤ 1 ┐ * nγwα φ , N p,Qd . * + ‖f‖ p,s s m* ┘ p,Q n,N \ ] * * i ng_e mma‘ana I nt hene ur alc as e,kl=1.Wege tmn,N=|JN,α(φ )(1)|.^s \ ] d* 1 d* * * l i m |JN,α(φ )(1)|=|φ (1)|,wehavemn,Ne |φ (1)|,whe r eN i sfi ge nough.ge nc e, Nb + c 2 (2h)i . sr i ght \ ] * .Wehavem* )|.ir I nt het r ans l at i onc as e,kl=l n |JN,α(φ )(l om _e mma‘ana n,N = mi └ 1 C wr f, n L ( ( ) ) - n≤ l ≤n ︵ d d* 1 * * )|=|φ* (l )|,weal )|,whe s oge tmn,Ne mi n |φ (l r eN i sfi ge nough.So l i m |JN,αφ (l Nb + c 2- n≤ l≤ n (2‘)i . sr i ght n,N Wr i t ejφ* ,J= q Σ Σ * d ml,lφ (nlx+o ,o nlpJrsq1r,ana l) lpQ , - n≤ l ≤ nk≤ l≤ N * φ ,s tn f)p,Qs = ,N ( * φ ,s * i nu ‖f- o , n,N ‖ p,s * φ ,s n,N * ,J o n,N p jφ t he nwege tt heu ol l owi ngvhe or e m. ~ d~ 1,α~ r~ 2,n~ 1,Ne Nn,anaal ._e wxy z{ y | }._e ts lout he m ar ei nt e ge r s tδ≤ d* η * p s ,1≤p≤+c,fpLp )≠k(l pZd).I anaφ pLQd s at i s u i e sφ (l uN i sfi ge nough, Q, N+Nn t he nt he r ee xi s t sac ons t antCekwhi c hs at i s u i e s * 1 φ ,s tn f)p,Qs ≤ Cwr f, ,N+ Nn( n ( ) s . (27) . (28) . (29) p,Q I nt hene ur alc as e, * 1 φ ,1 tn f)p,Qs ≤ Cwr f, ,N+ 1( n p,Q * 1 φ ,s tn f)p,Qs ≤ Cwr f, ,N+ n( n p,Q ( ) s I nt het r ans l at i onc as e, ( ) s * (α ) p .Whe P{ zzf nφ pLQd,weus evhe or e m 1t ooft ai n * 1 φ tn f)p,Qs ≤ C wr f, ,N+ Nn( n [( ) + s p,Q nγ * (α ) d ‖φ ‖* ‖* . p,Q ‖f p,s Nα (3k) .Mat .B {ppl h.J.Chi ne s eUni v.Se r 362 * .20,No.3 Vol * .I I f‖f‖ p,s=0,(27)i sobvi ous l yr i ght f‖f‖ p,s>0,(27)i sr i ghtagai n.Be c aus eN i s nr 1 * (α ) * * i r r e l e vantt onandN i sbi ge nough,wehave α‖φ ‖ p,Qd‖f‖ p,s≤wr f, n N ( ) . s p,Q Re f e r e nc e s 1 Mha s ka rH N,Mi c c he l l iCA.De gr e eofa ppr oxi ma t i onbyne ur a la ndt r a ns l a t i onne t wor kswi t hs i ngl e ,Adva 183. hi dde nl a ye r nc e di nAppl i e dMa t h,1995,16:1512 Di ,Ne t z i a nZ,Tot i kV.Modul iofSmoot hne s s w Yor k:Spr i nge r Ve r l a g,1987. 3 Suz ,Ne ukiShi n.Cons t r uc t i onf unc t i ona ppr oxi ma t i onbyt hr e el a ye ra r t i f i c i a lne ur a lne t wor ks ur a l ,1998,11(5):10491058. Ne t wor ks 4 ChuiCK,LiXi .I ,FIUt ,e ,Mul n.Ne ur a lne t wor kswi t honehi dde nl a ye r n:K J e t t e r r e r a s ds t i va r i a t e ,Si ,1993. Appr oxi ma t i on:Fr om CAGD t oWa ve l e t s nga por e:Wor l dSc i e nt i f i cPr e s s 5 XuZongbe ,Sc n,Ca oFe i l ong.Thee s s e nt i a lor de rofa ppr oxi ma t i onf orne ur a lne t wor ks i e nc ei nChi na 112. Se rF,I nf or ma t i onSc i e nc e,2004,47(1):976 Mha ,Si .Appr ,Pr s ka rH N,Na r c owi c hFJ va r kuma rN,e ta l oxi ma t i onwi t hi nt e r pol a t or yc ons t r a i nt s oc ,2001,130(5):13551364. Ame rMa t hSoc 7 Er ,JAppr 72. dy l yiT.Not e soni ne zua l i t i e swi t hdoubl ngwe i ght oxThe or y,1999,100(1):60- 8 Ma ,Cons s t r oi a nniG,Tot i k V.We i ght e dpol ynomi a li ne zua l i t i e swi t h doubl i nga nd{| we i ght s t r 71. Appr ox,2000,16(1):379 Ti ma nA F.The or yofAppr oxi ma t i onofFunc t i onsofA }e a lVa r i a bl e,Ne w Yor k:Ma c mi l l a nCo, 1963.(i n}us s i a n). 10 Sun Yongs he ng.The or y ofAppr oxi ma t i on ofFunc t i ons(~ ),Be i j i ng:Be i j i ng Nor ma lUni ve r s i t y ,1988:133137(i Pr e s s nChi ne s e). 11 Wa ngGua nmi n.Thea s ympt ot i cr e pr e s e nt a t i on oft hea ppr oxi ma t i on de gr e ef ort heJ a c ks on t ype 22(i ope r a t orJn,p(f,x),JZha ngz houTe a c he r sCol l e ge,1993,7(2):15nChi ne s e). 12 ,Ha Xi eTi ngf a n,Zhou Songpi ng.The or y ofAppr oxi ma t i on of}e a lFunc t i ons ngz hou:Ha ngz hou ,1997:154157(i Uni ve r s i t yPr e s s nChi ne s e). .ofMa De pt t h.,Ni ngboUni v.,Ni ngbo315211,Chi na.