吳柳嬋,陳曉玲
(廣東工業(yè)大學(xué) 應(yīng)用數(shù)學(xué)學(xué)院, 廣東 廣州 510520)
吳柳嬋,陳曉玲
(廣東工業(yè)大學(xué) 應(yīng)用數(shù)學(xué)學(xué)院, 廣東 廣州 510520)
拓?fù)涠壤碚撌茄芯糠蔷€性算子定性理論的有力工具,從它可推出許多著名的不動(dòng)點(diǎn)理論.研究非線性方程解的問題在理論上和應(yīng)用上都十分重要,但常用的解析工具(如壓縮映射)處理非唯一(例如出現(xiàn)分歧現(xiàn)象)的解卻無(wú)能為力.度理論的建立,為研究非線性方程多解問題提供了有力工具,它能導(dǎo)出非線性方程解的許多結(jié)果,還可推出許多著名的不動(dòng)點(diǎn)定理.因此,拓?fù)涠壤碚撝苯踊蜷g接地在物理、力學(xué)、微分方程等學(xué)科里獲得了廣泛的應(yīng)用.
為了討論問題方便起見,本文出現(xiàn)的空間E均為實(shí)非自反Banach空間(沒有特別說(shuō)明的情況下),E*為E的共軛空間,E**為E*的共軛空間,Ω?E**為非空有界開子集.
φ,T:ΩF→E*按范數(shù)拓?fù)溥B續(xù),則稱T為有限維連續(xù).
弱*收斂于f0=Tx0.
(1) 存在Ttx:[0,1]×D→E*為有限維連續(xù);
(2) 任取
弱*收斂于
弱*收斂于f0=Tt0x0.
弱*收斂于
則稱T為廣義偽單調(diào)映射.
對(duì)任意v∈F0都成立,其中d(·,·,·)為有限維空間連續(xù)映射的拓?fù)涠龋?/p>
(1)
(2)
證明 設(shè)xτ∈E**,fτ=Txτ,gτ=φxτ,xτ弱*收斂于x0,滿足
引理3[20]設(shè)E為實(shí)Banach空間,若E*可分,則E可分.
則存在有限維F0?E**,使得任意有限維空間F?F0,均有θ*?TFx,對(duì)任意x∈?ΩF都成立.
令WF={任取x∈?Ω,存在f=Tx,使得
對(duì)任意v∈F都成立}為有界集且WF≠φ
對(duì)任意v∈F,取F0,dimF0<+∞,使得
矛盾.故存在有限維F0?E**,使得任意有限維空間F?F0,均有θ*?TFx,對(duì)任意x∈?ΩF都成立.
對(duì)任意v∈F都成立}.則WF≠φ
是WF在[0,1]×E**的閉包.
使得tτ→t0,xτ弱*收斂于
由以上的命題,可定義
?F0,dimF<+∞,dimF0<+∞.
(2) 若Ω1,Ω2均是Ω的開子集,Ω=Ω1∪Ω2,Ω1∩Ω2=φ,則
證明 (1)和(2)的證明同有限維空間的性質(zhì)[22];
則
矛盾.
證明 假設(shè)F為Hilbert空間,則F*=F.對(duì)于有限維空間
?
φ.
則存在N>0,使得0?
?
對(duì)任意n>N,其中
弱*收斂于
矛盾.
任意v∈Fnk都成立.任取x∈Fnk,k=1,2,…,假設(shè)xτk弱*收斂于x0,同命題6的證明,有
弱*收斂于
對(duì)任意v∈Fnk矛盾.
證明 令
由命題7知,存在N1>0,N2>0,當(dāng)n>N1,N2時(shí),有
(3)
(4)
結(jié)合式(3)和(4),故
?
?E**非空有界開子集?E**的稠密子空間為的有限維空間序列?
滿足Ω∩Fn≠φ,若
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Wu Liu-chan,Chen Xiao-ling
2013- 06- 07
吳柳嬋(1989-),女,碩士研究生,主要研究方向?yàn)榉蔷€性泛函分析.
10.3969/j.issn.1007- 7162.2015.01.028
O177.91
A
1007-7162(2015)01- 0138- 05
(School of Applied Mathematics, Guangdong University of Technology, Guangzhou 510520,China)