您好,欢迎来到爱够旅游网。
搜索
您的当前位置:首页Banach空间之间C 1映射的广义正则点

Banach空间之间C 1映射的广义正则点

来源:爱够旅游网
维普资讯 http://www.cqvip.com Journal of Southeast University(English Edition) Vo1.23,No.1,PP.148—150 Mar.2007 ISSN 1003--7985 Generalized regular points of a C map between Banach spaces Shi Ping Ma Jipu。 ( Department of Applied Mathematics,Nanjing University of Finance nd Economiacs,Nanjing 210003,China) ( Department of Mathematics,Nanjing University,Nanjing 2 10093,China) Abstract:Letf be a C map between two Banach spaces E and F.It has been proved that the concept of generalized regulr apoints off,which is a generalization of he nottion of regulr poiants of{。has some crucila applications in nonlinearity and global analysis.We characterie tzhe generliazed regulr poiants of f using the three integer-valued(or infinite)indices M(xo),Mo(xo)and MAxo)at Xo∈E generated byfand by nalayzing generliaed zinverses of bounded linear operators on Banach spaces,that is,iff (Xo)has a generalied zinverse in he tBanach space坝E, ofal1 bounded 1inear operators on Einto F and at 1east one ofthe indices Xo), (Xo)and (Xo)is finite,then Xo is a generliaed rzegulr poiant off if nd onlay if het mulit-index(M( ), ( ),Mr( ))is continuous at Xo. Key words:Banach space;bounded linear operator;generalied iznverse;index;generalized regulr point;semi- aFredholm maD There are extensive applications of regular points Definition 1 Let f.-U c E—} be a C map. where Uis open in E.The pointx0∈Uis called a gen- and regulr valaues of a C mapping f between Banach spaces in nonlinear functional analysis and global anal— eralized regulr poiant of{ if there exists a generliazed inversef (x0) of f (x0)such that R(f ( ))n Ⅳ(f (x0) )={0)near x0,wheref ( )is the Fr6chet derivative offat ∈U. Defiitnion 2 Let f.-U c E—} be a C map, where U is open in E.A point Y∈F is called a general— ysis.The concept of locally fine points off was ifrst in- troduced in Ref.[1】,which is a generliazation of the notion of regulr poiants off nd hasa some importnta applications given in Refs.【2—3】.The generalized regulr vaalues off derived from the locally fine points offextend the contents of regulr vaalues offThe alm of this paper is to characterize the generalized regulr aized regulra value of f if and only if the preimage 厂 (),)is empty or only consists of generalized regulr apoints off. For a C mapping we give the following three indices. points of a C mapping f between two Banach spaces by a new approach. Let us recall some important concepts and nota- tions.Throughout this paper E and F denote Banach Defiitnion 3 Let|UC E F be a Cl mapping, where U is an open subset of E.For any ∈U.define spaces and。双E, is he tset of lal bounded linear op— erators on E into F.Let R( nd N(a )denote the ( )=dimN(f ( )),^ ( )=codimR(f ( ))and Mr(x)=dimR(f ( )). Clearly, ( ),^ ( ),^ (x)∈Z ,where Z =rnge aand null space of T∈坝E,F),respectively.An operator T ∈坝F,D is called a generalized inverse of T∈坝E,n,if 7T T=T nd T 7T =T Ia .Let f U CE F be a Cl mapping,where U is open in E.A point ∈U is called a regulra point forfif and only if fis a submersion at x,that is,the Fr6chet derivative f {0,1,2,…J U{o。). 1 Main Resuits We first 1ntroduce an auxiliary result,which is a ( )is surjective and the null spaceⅣ(f ( ))splits E. A point Y∈F is said to be a regulr vaalue off if and only if the setf (),)is empty or only consists of regu- solution of the local conjugacy problem suggested by Berger in Refs.【7—8】and can be found in Ref.[3】. Lemma 1 Let U c E be a C mapping lra points of ̄ . Received 20o6-06-l2. Foundation iterns:The National Namr ̄Science Foundation of China with a generlaized inverse of_厂( o),where U is an open subset containing o.Then f( )is conjugate to f (x0)near x0,that is,there exist two neighborhoods Ul of x0 and Vl of 0∈F wih two diftfeomorphisms u (No.10271053),the Foundation of Nanjing University of Finance and Economics(No.B0556). Biography:Shi Ping(1963一),male,associate professor,pshi@eyou. COm. on Ul and V on Vl such hatt U(Xo)=0,V(0)=,(Xo)and )=v(f (Xo)“( ))for all ∈Ul,ifand only ifx0 is a generlaized regulra point of f. 维普资讯 http://www.cqvip.com Generalized regular points of a C map between Banach spaces 149 Theorem 1 Suppose that} UCE F is a Cl mapping. 1)If Xo is a generalized regular point of then M(x),Mc(x)and Mr(x)are continuous at xo. 2)Iff (Xo)has a generalized inverse in钡F, nad at least one of the indices M( ), ( )and (x0)is finite,then Xo is a generalized regulra point off if and only if the mulit—index( ( ), ( ), ( ))is continuous at Xo. Proof 1)Since x0 is a generalized regulra point off,by lemma 1, x)is conjugate to f (xo)in the neighborhood U(xo)of xo,that is,there exist two dif- feomorphisms“: ) “(U(xo)),V: 0) V( 0)) such that u(x0)=0,v(0)= Xo)and x)=v(f ( o)u(x)) for all x∈ x0),where v(o)is a neighborhood at 0 F whence , ( )=v (, (Xo)u(x))f ( o)u r( ) for all x∈ x0). Let A(x)=v (, (Xo)u(x)),B(x)=u r( )for all x ∈ Xo).Since u and v are two diffeomorphisms,A(x) ∈坝F, and B(x)∈钡E,E)are invertible for any x∈U(x ).Then we have that f (x):A(x)f ( ) B(x),Ⅳ(f ( ))=B(x) N(f ( ))and R(f (x))= A(x)R(f (Xo))for all x∈ Xo).Hence dimN(f (x)) :dimN(f (Xo))and dimR(f ( )):dimR ( )) ofr all x∈U(xo). Since Xo is a generalized regulra point off,f ( 0) has a generalized inverse f ( 0) .Furthermore we can easily see that B(x) f ( 0) A( ) is a generlaized inverse off ( )for any x∈ xo).Hence R(f ( ))is closed for any x∈U(x0). Next we will claim that codimR(f ( )):codimR(f (Xo)) ofr all ∈ Xo).In fact,if codimR(f (而))<oo,then there exists a finite—dimensional complementary sub— space F.of R(f (Xo))in F,that is, F.0 R(f ( 。)):F nad dimFl:codimR(f ( o)) hTerefore A(x)Fl 0 A(x)R(f ( o))=F or A( )F.0R(f ( ))=F hTus codimR(f ( )):dimA(x)Fl=dimFl: codimR(f (Xo)) Suppose that codimR(, (x0))=oo,but codimR(f ( ))<oo for some x∈U(x0).By the oper- ator identityf ( ):A(x) f (x)B(x) and the above stated proof,we have that codimR(f (x0))= codirnR(f ( ))<oo,which is a contradiction.Hence M(x), ( )and ( )are constant in xo),whence M(x), ( )and ( )are continuous at Xo. 2)We only need to prove the sufifciency by 1). Since M(x), (x)and (x)are continuous at xo,there exists a neighborhood V at xo such that M(x) =M(xo), ( )=MAxo)and ( )=Mr(X0)for all x∈ It follows from the continuity off ( )at x0 that htere exists a neighborhood Vo ofXo such that ll, ( )一, ( 。)ll<lIf ( ) ll一 ofr all x∈Vo,wheref (X0) is a generalized inverse of f (Xo). Denote C(x)=IF+(f ( )--f (X0))f ( 。) and D(x)= +, (Xo) (f ( )一, ( o)) ofr all x∈Yo,where I Fand l Eare the identity operators on F and E,respectively.Then Ct ∈ tF,F and D(x)∈钡E,E)are invertible,and we obtain f ( ), (Xo) f ( o)=C(x)f ( o) f (Xo) f ( 。)D(x):, ( o) f ( ) D(x)f (Xo) :, ( 。) C(x) , ( ) C(x)~=D(x) f (Xo) ofr all x∈Vo.Therefore R(f ( )) R(C(x)f (Xo)) nad Ⅳ(厂 ( ) x) )=Ⅳ(厂 ( ) ) ofr all x∈Vo. We first assume that ( )<oo.Then dimR(f ( ))= (x)= (Xo)=dimR(f (Xo))<oo ofr all x∈ but dimR(f ( ))≥dimR(C(x)f (Xo))= dinaR(f (x0))for all x∈Vo,thus dimR(f (x))= dierR(C(x)f ( ))<oo for all x∈V n Vo,whence R(f ( ))=R(C(x)f ( o))for all x∈Vn Yo.Hence R(, ( ))nⅣ(, (x。) )=R(C(x)f (xo))n Ⅳ(, ( ) C(x) )={0}f0r all x∈VN Vo,that is,Xo is a generalized regulra point off. Now assume that (Xo)=oo,either M(xo)<oo or ( o)<oo. If M(xo)<oo,then dimN(f ( 。) f ( ))=dimD(x) Ⅳ(f (X0))= dimN(f (X0))=M(xo)<oo ofr all x∈Vo;however,M(x)=M(Xo)for all x∈V nadⅣ(f ( 0) f ( )) ^,(, ( )),thus dimN(f (X0) f ( ))=dimN(f ( ))<oo ofr all x∈VNVo,whence Ⅳ(f (X0) f ( ))=Ⅳ(f ( )) ofr all x∈VN Vo.Thus R(f ( ))nⅣ(, ( 0) ):{0} ofr all x∈VN Vo.Therefore xo is a generalized regular point off. If (Xo)<oo,we notice that dimN(f ( 0) )=codimR(f ( o))=^ ( o)<oo 维普资讯 http://www.cqvip.com l50 Shi Ping,and Ma Jipu then there exists a finite—dimensional complementary subspace N—of尺 ( ))nW (Xo) )in W (Xo) ), that is cjc =:(2jc 二:一 ‘—・2 : 二:一 ‘) fis a C Fredholm mapping,dimN(f (x)):1 and codimR(f (x)):1 for all x∈U.Sincef (x)is not Ⅳ(f (Xo) ):N一0[R(S ( ))nⅣ(f (Xo) )】 whence F:R(C(x)f (Xo))0Ⅳ(f (Xo) C(x) ): R(C(x)f (Xo))0N(f ( 0) ): R(S (x))+Ⅳ(f (Xo) ):R(S (x))0 N— for all x∈Vo.Thus surjective,f cannot have regular points and nontrivial regular values.By corollary 1,every x∈U is a gener— alized regulr poiant of{.Therefore f has nontrivial generalized regular values,e.g.,(e ,Y)(Y≠0)is a codimR(f ( )):dimN一:codimR(f (Xo)): dimN(f (Xo) )<。。 for all x∈vnVo.Therefore R(f (x))nN(f (Xo) ) :{0}for all x∈V n Vo.Hence Xo is a generalized egulrar point of f.This completes the proof. By theorem 1 and the concept of semi—Fredholm bounded linear operators【 ]on Banach spaces in the classical Fredholm operator theory,we have that nontrivial generalized regular value of f. References [1】Ma Jipu.(1.2)inverses of operators between Banach spaces and local conjugacy theorem[J】.Chinese Annals ofMath:Series B,1999,20(1):57—62. [2】Ma Jipu.Rank theorems of operators between Banach spaces fJ1.Science in China:Series A,20O0,43(1):l~5. Corollary 1 Letf:U(Xo)cE F be a C map— ping,where U(Xo)is an open subset containing x0 and [3】Ma Jipu.Local conjugacy theorem,rank theorems in ad— vanced calculus and a generalized principle for construc— f (Xo)∈坝E,F)be a semi—Fredholm operator with a generalized inverse.Then Xo is a generalized regular ting Banach manifolds[J】.Science in China,Series A, 2000.43(12):l233—1237. [4】Nashed M Z.Generalized inverses and applications[M】. New York:Academic Press.1976. point of f if and only if eihter dimN(f (x)): cUmN ̄e (Xo))<。。or codimR(f ( )):codimR(f (Xo)) <。。.near Xo. 【5】Nashed M Z,Chen X.Convergence of Newton—like meth— ods for singular operator equations using outer inverses [J】.NumerMath,1993,66:235—257. 2 Example We conclude this paper with a simple example,in [6】Zeidler E.Nonlinear functional analysis and its applica— tions:1V applications to mathematical physics[M】.New York:Springer—Verlag,1 988. which the C mapping f cannot have any regulr poiant and nontrivila regulr valaue,however f has generlaized egrular points and nontrivial generalized regulr vaalues. [7】Berger M S.Nonlinearity and unctfional analysis[M】. New York:Academic Press.1977. Example 1 Let U={x=(xl,x2)∈R } l 一x2 ≠0}CR2.f(x)is defined by,(x):(fl(x), ( )):R2一 R2,[8】Shi Ping,Ma Jipu.A note on a problem of M.S.Berger 【J】.Northeast Math J,2003,19(4):366—370. [9】Ma Jipu.Generalized indices of operators in B(H)[J】. Science in China:Series A,l997.40(12):l233—1238. wherefl(x):ex 一 ‘, ( ): l -x2 ,then Banach空间之间C 映射的广义正则点 史平 马吉溥 ( 南京财经大学应用数学系,南京210003) ( 南京大学数学系,南京210093) 摘要:设,是2个Banach空间E和F之间C 映射.已经证明,的广义正则点概念是,的正则点概 念的一个推广并且在非线性分析和大范围分析中有非常重要的应用.用.厂产生的在Xo∈E处的3 个整数(或无穷大)值指标M( ),M。( )和M ( )和分析Banach空间上有界线性算子的广义 逆来刻画,的广义正则点,即,如果, ( )在从E上到F的有界线性算子组成的Banach空间 以E,F)内有广义逆,且M(xo),M。( )和M (x。)中至少有一个是有限,则Xo是,的广义正则点 的充分必要条件是多重指标(M( ),M。( ),M ( ))在Xo点处连续. 关键词:Banach空间;有界线性算子;广义逆;指标;广义正则点;半Fredholm映射 中图分类号:O177.91 

因篇幅问题不能全部显示,请点此查看更多更全内容

Copyright © 2019- igbc.cn 版权所有 湘ICP备2023023988号-5

违法及侵权请联系:TEL:199 1889 7713 E-MAIL:2724546146@qq.com

本站由北京市万商天勤律师事务所王兴未律师提供法律服务