李燕,劉錫平,李曉晨,張莎
(上海理工大學(xué)理學(xué)院,上海 200093)
具有逐項分?jǐn)?shù)階導(dǎo)數(shù)的微分方程邊值問題解的存在性
李燕,劉錫平,李曉晨,張莎
(上海理工大學(xué)理學(xué)院,上海200093)
研究了一類具有逐項分?jǐn)?shù)階導(dǎo)數(shù)的微分方程邊值問題.對參數(shù)的各種取值情況進(jìn)行了全面的分析,運(yùn)用Banach壓縮映射原理和Schauder不動點(diǎn)定理,得到并證明了邊值問題解的存在性定理.最后,給出了兩個例子來證明結(jié)論有效.
分?jǐn)?shù)階微分方程;逐項分?jǐn)?shù)階導(dǎo)數(shù);邊值問題;Banach壓縮映射原理;Schauder不動點(diǎn)定理
近年來,由于分?jǐn)?shù)階微分方程在現(xiàn)代科學(xué)各個領(lǐng)域中的廣泛應(yīng)用,其理論研究備受關(guān)注[1].國內(nèi)外學(xué)者已對分?jǐn)?shù)階微分方程邊值問題進(jìn)行了大量研究(見參考文獻(xiàn)[2-11]).具有逐項分?jǐn)?shù)階導(dǎo)數(shù)的微分方程在振動理論中具有重要的意義,文獻(xiàn)[8-11]對于該類微分方程邊值問題進(jìn)行了研究.
文獻(xiàn)[9]研究了分?jǐn)?shù)階非線性微分方程邊值問題:
文獻(xiàn)[10]研究了如下具有逐項分?jǐn)?shù)階導(dǎo)數(shù)的微分方程三點(diǎn)邊值問題:
受上述文獻(xiàn)的的啟發(fā),本文研究如下具有逐項分?jǐn)?shù)階導(dǎo)數(shù)的微分方程邊值問題:
定義2.1[1]函數(shù)y:(0,∞)→R的α>0階Riemann-Liouville分?jǐn)?shù)階積分定義為:
等式右端在(0,∞)有定義.
定義2.2[1]連續(xù)函數(shù)y:(0,∞)→R的α>0階Caputo分?jǐn)?shù)階導(dǎo)數(shù)定義為:
只要等式右端在(0,∞)上有定義.
引理2.1[1]如果y∈Cn(0,1)∩L[0,1],則
其中n∈N,n-1<α<n,n=[α]+1.
引理2.3(Banach壓縮映像原理)設(shè)E是Banach空間X中的非空閉子集,映射T是E到自身的映象,如果對任意的x,y∈E,
則存在唯一的x∈E使得Tx=x.
引理2.4(Schauder不動點(diǎn)定理)設(shè)E是Banach空間X中的非空閉凸子集,F(xiàn)是E到E的連續(xù)映射,使F(E)是X中的相對緊子集,則F在E中至少有一個不動點(diǎn).
設(shè)C[0,1]為區(qū)間[0,1]上的連續(xù)函數(shù)空間,取范數(shù)為則C[0,1]為Banach空間.
我們首先估計Green函數(shù) Gi(t,s)的上界.
引理3.1由(5),(6),(7)定義的函數(shù) G1(t,s),G2(t,s),G3(t,s)有以下性質(zhì):
1)Gi(t,s)∈C([0,1]×[0,1]),i=1,2,3;
2)|Gi(t,s)|≤ki(s),i=1,2,3,
其中
顯然,邊值問題(1),(2)有解等價于映射 Si存在不動點(diǎn).
定理3.1假定 f:(0,1)×R→R是連續(xù)函數(shù),若存在(0,1)上可積函數(shù) L(t),并且∫使得
則對于參數(shù)的p,q的任意取值,當(dāng)pq≠0時,邊值問題(1),(2)都有唯一解.
定理3.2 假定 f:(0,1)×R→R,且存在正常數(shù)M,Ni使得
其中Ni滿足
這里ki(t)分別由(10),(11),(12)式定義,那么邊值問題(1),(2)式至少有一個解.
為了證明結(jié)論的有效性,給出下面的例子.
例4.1考慮邊值問題
例4.2考慮邊值問題
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2010 MSC:34A08,34B08,34B15
Existence of solutions for boundary value problem of fractional differential equations involving sequential fractional derivative
Li Yan,Liu Xiping,Li Xiaochen,Zhang Sha
(College of Science,University of Shanghai for Science and Technology,Shanghai200093,China)
This paper investigates the existence of solutions for boundary value problem of fractional differential equations involving sequential fractional derivative.To analyze comprehensively the parameters and by using Banach contraction mapping principle and Schauder fixed point theorem,some new results on the existence of solution for the boundary value problem are obtained.Finally,we give two examples to illustrate our results.
fractional differential equation,sequential fractional derivative,boundary value problem,Banach contraction mapping principle,Schauder fixed point theorem
O175.8
A
1008-5513(2016)05-0470-11
10.3969/j.issn.1008-5513.2016.05.004
2016-05-12.
國家自然科學(xué)基金(11171220);滬江基金(B14005).
李燕(1991-),碩士生,研究方向:常微分方程理論與應(yīng)用.
劉錫平(1962-),碩士,教授,研究方向:常微分方程理論與應(yīng)用.