李 向 有
(延安大學(xué) 數(shù)學(xué)與計(jì)算機(jī)學(xué)院, 陜西 延安 716000)
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非光滑多目標(biāo)分式規(guī)劃的對(duì)偶條件
李 向 有
(延安大學(xué) 數(shù)學(xué)與計(jì)算機(jī)學(xué)院, 陜西 延安 716000)
最優(yōu)性問題在研究博弈理論、目標(biāo)規(guī)劃、最低風(fēng)險(xiǎn)問題等方面有重要應(yīng)用,利用非光滑分析,定義了一類新的廣義不變凸函數(shù),研究了涉及此類函數(shù)的多目標(biāo)半無限分式規(guī)劃問題, 得到了參數(shù)對(duì)偶問題的弱對(duì)偶和嚴(yán)格逆對(duì)偶條件,在新的凸性下得到了一些重要結(jié)論.
廣義不變凸函數(shù);多目標(biāo);對(duì)偶;分式規(guī)劃
推廣凸函數(shù)是最優(yōu)化理論一個(gè)重要的研究方向, ANTCZAK[1]在B凸函數(shù)和(p,r)凸函數(shù)的基礎(chǔ)上定義了可微B-(p,r)凸函數(shù),并用其研究單目標(biāo)規(guī)劃問題,文獻(xiàn)[2-7]在B-(p,r)凸函數(shù)的基礎(chǔ)上推廣了不變凸函數(shù),用于研究不同類型的規(guī)劃問題,并得到了大量有益的結(jié)果. 雖然利用B-(p,r)凸函數(shù)研究規(guī)劃的文獻(xiàn)不少,但大多是利用可微B-(p,r)凸函數(shù)討論單目標(biāo)規(guī)劃問題和多目標(biāo)可微規(guī)劃問題,涉及多目標(biāo)非光滑規(guī)劃問題的研究很少. 利用非光滑分析研究多目標(biāo)規(guī)劃問題已成為近年來研究的熱點(diǎn),文獻(xiàn)[8-10]利用不同的凸函數(shù)研究了非光滑多目標(biāo)規(guī)劃問題,得到了許多重要結(jié)果.
本文在上述研究的基礎(chǔ)上,定義了一類B-(p,r,a)不變凸函數(shù)、B-(p,r,a)不變擬凸函數(shù)、B-(p,r,a)不變偽凸函數(shù),研究多目標(biāo)半無限分式規(guī)劃的對(duì)偶問題,在新的凸性下,得到了一些重要結(jié)果.
若對(duì)任意x∈Rn,存在一個(gè)正數(shù)k和x的鄰域N(x),對(duì)任意y,z∈N(x),使得
‖f(y)-f(z)‖≤k‖y-z‖,
則稱實(shí)值函數(shù)f:Rn→R是局部Lipschitz的[11].
若函數(shù)f為局部Lipschitz的,那么函數(shù)f:X→R在點(diǎn)x處沿方向d的Clarke廣義方向?qū)?shù)和Clarke廣義梯度分別定義為[11]:
?f(x)={ξ∈Rn:f0(x;d)≥ξTd,?d∈Rn}.
注 對(duì)于任意x,y∈Rn,下面變量間的序關(guān)系始終成立:
已有文獻(xiàn)在利用B-(p,r)凸函數(shù)討論規(guī)劃問題時(shí),只討論B-(p,r)凸函數(shù)中的1種,其他3種情況類似可證. 本文也照此思路,只給出在p,r≠0時(shí)B-(p,r,a)不變凸函數(shù)的定義.
定義1 設(shè)非空開集X?Rn,f:X→R是X上的局部Lipschitz函數(shù),p,r是任意非零實(shí)數(shù),u∈X,若?x∈X,存在向量函數(shù)η:X×X→Rn,函數(shù)b:X×X→R+(R+是非負(fù)實(shí)數(shù)),a:X×X→R,使得對(duì)?ξ∈?f(u)有
則稱f在u點(diǎn)為關(guān)于函數(shù)η的B-(p,r,a)不變凸函數(shù).
定義2 設(shè)非空開集X?Rn,f:X→R是X上的局部Lipschitz函數(shù),p,r是任意非零實(shí)數(shù), u∈X, 若?x∈X,存在向量函數(shù)η:X×X→Rn,函數(shù)b:X×X→R+(R+是非負(fù)實(shí)數(shù)),a:X×X→R,對(duì)?ξ∈?f(u)有
則稱f在u點(diǎn)為關(guān)于函數(shù)η的B-(p,r,a)不變擬凸函數(shù).
定義3 設(shè)非空開集X?Rn,f:X→R是X上的局部Lipschitz函數(shù),p,r是任意非零實(shí)數(shù),u∈X,若?x∈X,存在向量函數(shù)η:X×X→Rn,函數(shù)b:X×X→R+(R+是非負(fù)實(shí)數(shù)),a:X×X→R,使得對(duì)?ξ∈?f(u)有
則稱f在u點(diǎn)為關(guān)于函數(shù)η的B-(p,r,a)不變偽凸函數(shù).其中,I=(1,1,…,1)∈Rn,e(a1,a2,…,an)=(ea1,ea2,…,ean)∈Rn.
考慮下列多目標(biāo)半無限分式規(guī)劃問題:
s.t h(x,u)0,
x∈X0?Rn, u∈Y?Rn,
其中,fi:Rn→R,gi:Rn→R(i=1,2,…,m),h(x,u):Rn×Rn→R均為局部Lipschitz的實(shí)值函數(shù),并假設(shè)fi(x)≥0,gi(x)>0,i=1,2,…,m,Y為無限可數(shù)參數(shù)集.記Δ={jh(x,uj)0,uj∈Y?Rn},是可數(shù)指標(biāo)集,假定下面出現(xiàn)的關(guān)于h(x,u)的廣義級(jí)數(shù)都是絕對(duì)收斂的.
(FP)的對(duì)偶規(guī)劃定義為
(FD)Max v=(v1,v2,…,vm),
(1)
fi(y)-vigi(y)0, i=1,2,…,m,
(2)
τjh(y,uj)0, j∈Δ,
(3)
(4)
定理2(弱對(duì)偶) 令
(1)x,(y,λ,τ,v)分別是(FP)和(FD)的可行解;
(3) a(x,y)+c(x,y)≥0.
fi(x)-vigi(x)≤0, i=1,2,…,m,
且至少存在某個(gè)k,fk(x)-vkgk(x)<0.
結(jié)合式(2),可以得到
(5)
由式(1)可知,?ξi∈?fi(y),μi∈?gi(y),δj∈?h(y,uj),有
(6)
由式(5),(6)和a(x,y)+c(x,y)≥0,可得
即
(7)
又x,(y,λ,τ,v)分別是(FP)和(FD)的可行解,故τjh(x,uj)0,τjh(y,uj)0, 這與式(7)矛盾,故假設(shè)不成立.
證明 類似于文獻(xiàn)[12]定理2的證明.
定理4(嚴(yán)格逆對(duì)偶) 令
(1)x0,(y,λ,τ,v)分別是(FP)和(FD)的可行解;
(3)a(x0,y)+c(x0,y)>0.
則x0=y,即y也是(FP)的有效解.
證明 由推論1可知,x0,(y,λ,τ,v)分別是(FP)和(FD)的有效解.假設(shè)x0≠y,因?yàn)閤0,(y,λ,τ,v)分別是(FP)和(FD)的可行解,所以 τjh(x0,uj)0τjh(y,uj),即有
(8)
由式(1)可知,?ξi∈?fi(y),μi∈?gi(y),δj∈?h(y,uj),有
(9)
由式(8),(9)和a(x0,y)+c(x0,y)>0,可得
即有
而這與式(2)矛盾,故x0=y,即y也是(FP)的有效解.
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LI Xiangyou
(InstituteofMathematicsandComputerScienceofYan’anUniversity,Yan’an716000,ShaanxiProvince,China)
Duality conditions of nonsmooth multi-objective fractional programming. Journal of Zhejiang University(Science Edition), 2016,43(6):682-684
Optimization plays an important role in game theory, goal programming, minimum risk problems, etc. By nonsmooth analysis, a new class of invex functions are defined, and multi-objective semi-infinite fractional programming problems involving the new defined invex functions are investigated. Then, weak dual conditions and strictly converse dual conditions of parameter dual problems are obtained, and some important conclusions are also drawn under the new convexity.
generalized invex functions ; multiobjective ; duality ; fractional programming
2015-08-22.
國家自然科學(xué)基金資助項(xiàng)目(11471007);陜西省教育廳科研項(xiàng)目資助課題( 14JK1840).
李向有(1976-),ORCID:http://orcid.org/0000-0002-3761-1118,男,碩士,副教授,主要從事最優(yōu)化理論與應(yīng)用研究,E-mail: yadxlxy@163.com.
10.3785/j.issn.1008-9497.2016.06.011
O 221.6;O 224
A
1008-9497(2016)06-682-03