常慧杰,桑彥彬
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對稱空間中滿足弱壓縮條件及公共極限值域性質(zhì)的4個非自映射不動點定理
常慧杰[1],桑彥彬
(中北大學 理學院,山西 太原 030051)
利用公共極限值域性質(zhì),在映射滿足弱壓縮條件情況下,建立了一類在對稱空間中2對非自映射公共不動點的存在定理.
弱壓縮;公共不動點;公共極限值域性質(zhì)
1引言及預備知識
近年來,4個映射的公共不動點定理受到了廣泛的關(guān)注,文獻[1]研究了對稱空間中4個自映射的公共不動點定理,此映射滿足性質(zhì)和弱相容條件,并舉出相應的例子.進一步,文獻在對稱空間中,將性質(zhì)改為公共極限值域性質(zhì),4個自映射變成4個非自映射,并得到相應的不動點定理.
定義1[3]若滿足條件:
定義2[4-5]設是對稱空間,那么
定義3[6]令和是定義在具有對稱距離的非空集合上的2個自映射,若對于任意,當時,恒有,則稱為弱相容.
定義4[7]設是任意的集合,是定義在上的2個非自映射,若在中存在序列,使得,其中:,則稱在上具有公共極限值域性質(zhì)(記作).
定義5[8]設是任意的集合,和是定義在上的4個非自映射.若在中存在2個序列,,使得,其中:,則稱映射對和在上具有公共極限值域性質(zhì)(記作).
引理[9]令,則,且時,.
本文利用公共極限值域性質(zhì),借助度量空間中Cauchy列的收斂性及弱壓縮算子的概念及其性質(zhì),將文獻[2]中的算子進行變換,得到4個非自映射公共不動點定理的相應結(jié)論.關(guān)于4個非自映射不動點定理更一般結(jié)論的進一步討論可參見文獻[10];關(guān)于對稱空間中一些更一般的結(jié)論可參見文獻[11].
2主要結(jié)果及證明
假定下列條件成立:
生姜皮 生姜皮為生姜的外皮,辛涼力緩,和脾利水,善治水腫、小便不利,常配茯苓皮、桑白皮、大腹皮等治各種水腫,起利水消腫作用。
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Fixed point theorems for four non-self mappings in symmetric spaces satisfyingweakly contractive conditions and common limit range property
CHANG Hui-jie,SANG Yan-bin
(School of Science,North University of China,Taiyuan 030051,China)
Utilizing the common limit range property,the existence results of common fixed points for two pairs of non-self weakly compatible mappings satisfyingweakly contractive conditions are established .
weakly contractive;common fixed points;common limit range property
O177.91
A
10.3969/j.issn.1007-9831.2016.03.003
2016-01-14
中北大學?;痦椖?/p>
常慧杰(1989-),男,山西太原人,在讀碩士研究生,從事非線性泛函研究.E-mail:852740174@qq.com
桑彥彬(1979-),男,山西澤州人,副教授,博士,從事非線性泛函分析研究.E-mail:sangyanbin@126.com