Hybrid-type generalized multivalued vector complementarity problems

We introduce a new type of generalized multivalued vector complementarity problems with moving pointed cone. We discuss the existence results for generalized multivalued vector complementarity problems under inclusive assumptions and obtain results on the equivalence between the generalized multival...

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
id nasplib_isofts_kiev_ua-123456789-164923
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spelling Agarwal, R.P.
Ahmad, M.K.
Salahuddin
2020-02-11T10:49:41Z
2020-02-11T10:49:41Z
2013
Hybrid-type generalized multivalued vector complementarity problems / R.P. Agarwal, M.K. Ahmad, Salahuddin // Український математичний журнал. — 2013. — Т. 65, № 1. — С. 7-20. — Бібліогр.: 16 назв. — англ.
1027-3190
https://nasplib.isofts.kiev.ua/handle/123456789/164923
517.9
We introduce a new type of generalized multivalued vector complementarity problems with moving pointed cone. We discuss the existence results for generalized multivalued vector complementarity problems under inclusive assumptions and obtain results on the equivalence between the generalized multivalued vector complementarity problems and the generalized multivalued vector variational inequality problems.
Введено новий тип узагальнених багатозначних векторних задач доповнюваностi з рухомим загостреним конусом. Розглянуто питання про iснування розв’язкiв узагальнених багатозначних векторних задач доповнюваностi при умовах включення та отримано результати щодо еквiвалентностi мiж узагальненими багатозначними векторними задачами доповнюваностi та узагальненими багатозначними векторними задачами для варiацiйних нерiвностей.
en
Інститут математики НАН України
Український математичний журнал
Статті
Hybrid-type generalized multivalued vector complementarity problems
Узагальненi багатозначнi векторнi задачi доповнюваностi гiбридного типу
Article
published earlier
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
collection DSpace DC
title Hybrid-type generalized multivalued vector complementarity problems
spellingShingle Hybrid-type generalized multivalued vector complementarity problems
Agarwal, R.P.
Ahmad, M.K.
Salahuddin
Статті
title_short Hybrid-type generalized multivalued vector complementarity problems
title_full Hybrid-type generalized multivalued vector complementarity problems
title_fullStr Hybrid-type generalized multivalued vector complementarity problems
title_full_unstemmed Hybrid-type generalized multivalued vector complementarity problems
title_sort hybrid-type generalized multivalued vector complementarity problems
author Agarwal, R.P.
Ahmad, M.K.
Salahuddin
author_facet Agarwal, R.P.
Ahmad, M.K.
Salahuddin
topic Статті
topic_facet Статті
publishDate 2013
language English
container_title Український математичний журнал
publisher Інститут математики НАН України
format Article
title_alt Узагальненi багатозначнi векторнi задачi доповнюваностi гiбридного типу
description We introduce a new type of generalized multivalued vector complementarity problems with moving pointed cone. We discuss the existence results for generalized multivalued vector complementarity problems under inclusive assumptions and obtain results on the equivalence between the generalized multivalued vector complementarity problems and the generalized multivalued vector variational inequality problems. Введено новий тип узагальнених багатозначних векторних задач доповнюваностi з рухомим загостреним конусом. Розглянуто питання про iснування розв’язкiв узагальнених багатозначних векторних задач доповнюваностi при умовах включення та отримано результати щодо еквiвалентностi мiж узагальненими багатозначними векторними задачами доповнюваностi та узагальненими багатозначними векторними задачами для варiацiйних нерiвностей.
issn 1027-3190
url https://nasplib.isofts.kiev.ua/handle/123456789/164923
citation_txt Hybrid-type generalized multivalued vector complementarity problems / R.P. Agarwal, M.K. Ahmad, Salahuddin // Український математичний журнал. — 2013. — Т. 65, № 1. — С. 7-20. — Бібліогр.: 16 назв. — англ.
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first_indexed 2025-11-25T22:47:35Z
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fulltext UDC 517.9 R. P. Agarwal (Texas A&M University-Kingsville, USA), Salahuddin, M. K. Ahmad (Aligarh Muslim Univ., India) HYBRID TYPE GENERALIZED MULTIVALUED VECTOR COMPLEMENTARITY PROBLEMS УЗАГАЛЬНЕНI БАГАТОЗНАЧНI ВЕКТОРНI ЗАДАЧI ДОПОВНЮВАНОСТI ГIБРИДНОГО ТИПУ We introduce a new type of generalized multivalued vector complementarity problems with moving pointed cone. We discuss the existence results for generalized multivalued vector complementarity problems under inclusive assumptions and obtain results on the equivalence between the generalized multivalued vector complementarity problems and the generalized multivalued vector variational inequality problems. Введено новий тип узагальнених багатозначних векторних задач доповнюваностi з рухомим загостреним конусом. Розглянуто питання про iснування розв’язкiв узагальнених багатозначних векторних задач доповнюваностi при умовах включення та отримано результати щодо еквiвалентностi мiж узагальненими багатозначними векторними задачами доповнюваностi та узагальненими багатозначними векторними задачами для варiацiйних нерiвностей. 1. Introduction and preliminaries. The purpose of this paper is to introduce and discuss a new type of generalized multivalued vector complementarity problem with moving pointed cone which is a variable ordering relation. We derive existence of solutions for this class of generalized multivalued vector complementarity problems under inclusive type assumptions. This inclusive conditions require that any two of the family which is closed and convex satisfy an inclusion relation so long as their corresponding variable satisfy certain conditions. We have also obtained some equivalence results among a generalized multivalued vector complementarity problem, a generalized multivalued vector variational inequality problem, a generalized multivalued weak minimal element problem and a generalized multivalued vector unilateral optimization problem under some monotonicity conditions and some inclusive type assumptions in ordered Banach spaces. The theorems presented in this paper improved, extended and developed some earlier and very recent results in the literature including [2, 4 – 6, 8, 9, 11]. Motivated and inspired by these works [1, 3, 7, 8, 12 – 16], in this paper we initiate three types of generalized multivalued vector complementarity problems. Let X, Y be the two Banach spaces, P : D → 2Y a multivalued mapping such that for each x ∈ D,P (x) is a proper, closed, convex and pointed moving cone with apex at the origin and intP (x) 6= ∅. Let Q(·, ·) : D × L(X,Y ) → → L(X,Y ), g : D → Y be the single-valued mappings and A : X → 2L(X,Y ) be the multivalued mapping, where 2L(X,Y ) is a collection of all nonempty subsets of L(X,Y ). We consider the follow- ing three kinds of generalized multivalued vector complementarity problems. Weakly generalized multivalued vector complementarity problem (WGMVCP): finding x ∈ D and u ∈ A(x) such that 〈Q(x, u), g(x)〉 6≥intP (x) 0, 〈Q(x, u), g(y)〉 6≤intP (x) 0 ∀y ∈ D. (1.1) Positive generalized multivalued vector complementarity problem (PGMVCP): finding x ∈ D and u ∈ A(x) such that c© R. P. AGARWAL, SALAHUDDIN, M. K. AHMAD, 2013 ISSN 1027-3190. Укр. мат. журн., 2013, т. 65, № 1 7 8 R. P. AGARWAL, SALAHUDDIN, M. K. AHMAD 〈Q(x, u), g(x)〉 6>intP (x) 0, 〈Q(x, u), g(y)〉 ≥P (x) 0 ∀y ∈ D. (1.2) Strong generalized multivalued vector complementarity problem (SGMVCP): finding x ∈ D and u ∈ A(x) such that 〈Q(x, u), g(x)〉 = 0, 〈Q(x, u), g(y)〉 ≥P (x) 0 ∀y ∈ D. (1.3) Remark 1.1. If we take g an identity mapping and Q(x, u) = Q(u), then these generalized multivalued vector complementarity problems reduce to the following types of complementarity problems in Ceng and Lin [1]. Generalized weak vector complementarity problem (GWVCP): finding x ∈ D and u ∈ A(x) such that 〈Q(u), x〉 6≥intP (x) 0, 〈Q(u), y〉 6≤intP (x) 0 ∀y ∈ D. (1.4) Generalized positive vector complementarity problem (GPVCP): finding x ∈ D and u ∈ A(x) such that 〈Q(u), x〉 6>intP (x) 0, 〈Q(u), y〉 ≥P (x) 0 ∀y ∈ D. (1.5) Generalized strong vector complementarity problem (GSVCP): finding x ∈ D and u ∈ A(x) such that 〈Q(u), x〉 = 0, 〈Q(u), y〉 ≥P (x) 0 ∀y ∈ D. (1.6) Again we remark that, if A : X → L(X,Y ) and Q an identity mapping then aforesaid three kinds of problems reduce to the problem of Huang et al [8]. (Weak) vector complementarity problem (VCP): finding x ∈ D such that 〈A(x), x〉 6≥intP (x) 0, 〈A(x), y〉 6≤intP (x) 0 ∀y ∈ D. (1.7) Positive vector complementarity problem (PVCP): finding x ∈ D such that 〈A(x), x〉 6>intP (x) 0, 〈A(x), y〉 ≥P (x) 0 ∀y ∈ D. (1.8) Strong vector complementarity problem (SVCP): finding x ∈ D such that 〈A(x), x〉 = 0, 〈A(x), y〉 ≥P (x) 0 ∀y ∈ D. (1.9) We note that if P (x) = P for all x ∈ D, where P is a closed, pointed and convex cone in Y with nonempty interior intP (x), then all these problems are equivalent to problems considered in Chen and Yang [3]. 2. Existence of a solution for GMVCP. In this section, we extend their results to the cases involving the multivalued mappings. Let X be an arbitrary real Hausdorff topological vector space and Y a Banach space. Let L(X,Y ) denotes the space of all continuous linear mappings from X to Y. Let D be a nonempty subset of X and P : D → 2Y a multivalued mapping such that for each x ∈ D, P (x) is a proper, closed, convex and pointed moving cone with apex at the origin and intP (x) 6= ∅. Let K be a subset of Y. For each x ∈ D, a point z ∈ K is called a minimal point of K with respect to the cone P (x) ISSN 1027-3190. Укр. мат. журн., 2013, т. 65, № 1 HYBRID TYPE GENERALIZED MULTIVALUED VECTOR COMPLEMENTARITY PROBLEMS 9 if K ∩ (z − P (x)) = {z}; MinP (x)K is the set of all minimal points of K with respect to the cone P (x); a point z ∈ K is called a weakly minimal point of K with respect to the cone P (x) if K ∩ (z− intP (x)) = ∅; MinwP (x)K is the set of all weakly minimal points of K with respect to the cone P (x), for details see [11]. Let Q : D × L(X,Y ) → L(X,Y ) and g : D → Y be the single-valued mappings and A : X → → 2L(X,Y ) be the multivalued mapping. Consider the generalized multivalued vector complementar- ity problem (GMVCP): finding x ∈ D and u ∈ A(x) such that 〈Q(x, u), g(x)〉 6≥intP (x) 0, 〈Q(x, u), g(y)〉 6≤intP (x) 0 ∀y ∈ D. (2.1) A feasible set of (GMVCP) is Ω = { (x, u) ∈ D ×A(D) : u ∈ A(x), 〈Q(x, u), g(y)〉 6≤intP (x) 0 ∀y ∈ D } . (2.2) We consider the following generalized multivalued vector optimization problem (GMVOP): MinP 〈Q(x, u), g(x)〉 subject to (x, u) ∈ Ω. (2.3) A point (x, u) ∈ Ω is called a weakly minimal solutions of (GMVOP) with respect to the cone P (x) if 〈Q(x, u), g(x)〉 is a weakly minimal point of (GMVOP) with respect to the cone P (x), that is 〈Q(x, u), g(x)〉 ∈ MinwP (x) { 〈Q(x, u), g(x)〉 : (x, u) ∈ Ω } . We represent the set of all weakly minimal solutions of (GMVOP) with respect to the cone P (x) by ζwP (x) and the set of all weakly minimal solutions of (GMVOP) by ζw, that is ζw = ⋃ x∈D ζwP (x). (2.4) Theorem 2.1. If ζw 6= ∅ and, for some x ∈ D, there exists (x, u) ∈ ζwP (x) such that 〈Q(x, u), g(x)〉 6≥intP (x) 0, then generalized multivalued vector complementarity problem (GMVCP) is solvable. Proof. Let (x, u) ∈ ζwP (x) and 〈Q(x, u), g(x)〉 6≥intP (x) 0, (2.5) then x ∈ D, u ∈ A(x) and 〈Q(x, u), g(x)〉 6≥intP (x) 0, 〈Q(x, u), g(x)〉 6≤intP (x) 0 ∀y ∈ D. Therefore, x is a solution of (GMVCP). Theorem 2.1 is proved. Remark 2.1. If Q(x, u) = Q(u) and g is an identity mapping, then Theorem 2.1 coincides with Theorem 2.1 in Ceng and Lin [1]. Again if Q ≡ I, the identity mapping of L(X,Y ) and A is a single-valued mapping from D = X to L(X,Y ), then Theorem 2.1 coincides with Theorem 2.1 of Huang et al. [8]. ISSN 1027-3190. Укр. мат. журн., 2013, т. 65, № 1 10 R. P. AGARWAL, SALAHUDDIN, M. K. AHMAD Definition 2.1. Let A : D → 2L(X,Y ), P : D → 2Y be the two multivalued mappings with intP (x) 6= ∅ for every x ∈ D, Q : D × L(X,Y ) → L(X,Y ) and g : D → Y be the two single- valued mappings and Ω a subset of D × A(D). We say that P is inclusive with respect to Ω if for any (x, u), (y, v) ∈ Ω, 〈Q(x, u), g(x)〉 ≤intP (y) 〈Q(x, v), g(y)〉 implies that P (x) ⊂ P (y). (2.6) It is easy to see that, if P (x) = P for all x ∈ D, where P is a closed, pointed and convex moving cone in Y, then P is inclusive with respect to Ω. Theorem 2.2. Suppose that P is inclusive with respect to Ω. If there exists at most finite num- ber of solutions for (GMVCP), then (GMVCP) is a solvable if and only if ζw 6= ∅ and there exists (x, u) ∈ ζwP (x) such that 〈Q(x, u), g(x)〉 6≥intP (x) 0. Proof. Let ρ1 be a solution of (GMVCP), then there exists u1 ∈ Aρ1 such that 〈Q(ρ1, u1), g(ρ1)〉 6≥intP (ρ1) 0, 〈Q(ρ1, u1), g(y)〉 6≤intP (ρ1) 0 ∀y ∈ D. (2.7) If (ρ1, u1) ∈ ζwP (ρ1) , then 〈Q(ρ1, u1), g(ρ1)〉 6≥intP (ρ1) 0, (2.8) and hence the conclusion holds. If (ρ1, u1) 6∈ ζwP (ρ1) , by the definition of a weakly minimal solution there exists (ρ2, u2) ∈ Ω such that 〈Q(ρ2, u2), g(y)〉 6≤intP (ρ2) 0 ∀y ∈ D, (2.9) 〈Q(ρ2, u2), g(ρ2)〉 ≤intP (ρ1) 〈Q(ρ1, u1), g(ρ1)〉 6≥intP (ρ1) 0. This implies that 〈Q(ρ2, u2), g(ρ2)〉 6≥intP (ρ1) 0. (2.10) Since 〈Q(ρ2, u2), g(ρ2)〉 ≤intP (ρ1) 〈Q(ρ1, u1), g(ρ1)〉, and P is inclusive with respect to Ω, it follows that P (ρ2) ⊂ P (ρ1), and this implies that 〈Q(ρ2, u2), g(ρ2)〉 6≥intP (ρ2) 0. (2.11) Thus ρ2 is a solution of (GMVCP) and ρ2 6= ρ1. Continuing this process there exists (ρn, un) ∈ Ω such that ρn is a solution of (GMVCP) and (ρn, un) ∈ ζwP (ρn) , since (GMVCP) has almost a finite number of solutions. Thus 〈Q(ρn, un), g(ρn)〉 ∈ MinwP (ρn) { 〈Q(x, u), g(ρn)〉 : (ρn, u) ∈ Ω } and 〈Q(ρn, un), g(ρn)〉 6≥intP (ρn) 0. (2.12) Combining this result and Theorem 2.1, we have the conclusion of the theorem. ISSN 1027-3190. Укр. мат. журн., 2013, т. 65, № 1 HYBRID TYPE GENERALIZED MULTIVALUED VECTOR COMPLEMENTARITY PROBLEMS 11 Remark 2.2. If Q(x, u) = Q(u) and g is an identity mapping then Theorem 2.2 reduces to the Theorem 2.4 of Ceng and Lin [1]. If Q ≡ I is an identity mapping, A is single-valued mapping from X to L(X,Y ) and P (x) = P for all x ∈ X, where P is a closed pointed and convex moving cone in Y, then P (x) satisfies the inclusive assumption with respect to Ω and Theorem 2.2 is equivalent to the Theorem 3.2 of Chen and Yang [3]. We note that if Q ≡ I, the identity mapping of L(X,Y ) and A is a single-valued mapping from D = X to L(X,Y ), then Theorem 2.2 coincides with Theorem 2.2 of Huang et al. [8]. Next we consider the positive generalized multivalued vector complementarity problem (PG- MVCP): finding x ∈ D,u ∈ A(x) such that 〈Q(x, u), g(x)〉 6≥intP (x) 0, 〈Q(x, u), g(y)〉 ≥P (x) 0, y ∈ D. (2.13) Let ψ = {(x, u) ∈ D ×A(D) : u ∈ A(x), 〈Q(x, u), g(y)〉 ≥P (x) 0 ∀y ∈ D}. (2.14) Consider the following generalized multivalued vector optimization problem (GMVOP) to be MinP 〈Q(x, u), g(x)〉 subject to (x, u) ∈ ψ. (2.15) We denote the set of all minimal point of (GMVOP) with respect to the moving cone P (x) by ΓP (x), that is ΓP (x) = MinP (x){〈Q(x, u), g(x)〉 : (x, u) ∈ ψ} and denote the set of all minimal point of (GMVOP) by Γ = ⋃ x∈D ΓP (x). (2.16) Theorem 2.3. If Γ 6= ∅ and there exists (x, u) ∈ ΓP (x) such that 〈Q(x, u), g(x)〉 6≥intP (x) 0, then (PGMVCP) is solvable. Theorem 2.4. Suppose that P is inclusive with respect to ψ. If there exists at most a finite number of solutions of (PGMVCP), then (PGMVCP) is solvable if and only if Γ 6= ∅ and there exists (x, u) ∈ ΓP (x) such that 〈Q(x, u), g(x)〉 6≥intP (x) 0. (2.17) We note that if Q(x, u) = Q(u) and g is an identity mapping then Theorem 2.3 and 2.4 coincide with Theorem 2.6 and 2.7 of Ceng and Lin [1]. Also again if Q ≡ I is an identity mapping of L(X,Y ) and A is a single-valued mapping from D = X to L(X,Y ), then Theorem 2.3 and 2.4 is similar to Theorem 2.3 and 2.4 of Huang et al. [8]. 3. Equivalence between the generalized multivalued vector complementarity problems and generalized multivalued weak minimal element problems. LetX, Y be the two Banach spaces and P : D → 2Y a multivalued mapping such that for each x ∈ D,P (x) is a proper, closed, convex and pointed moving cone with apex at the origin and intP (x) 6= ∅. Let Q : D × L(X,Y ) → L(X,Y ) ISSN 1027-3190. Укр. мат. журн., 2013, т. 65, № 1 12 R. P. AGARWAL, SALAHUDDIN, M. K. AHMAD and g : D → D the single-valued mappings, A : X → 2L(X,Y ) the multivalued mapping, where 2L(X,Y ) is a collection of all nonempty subsets of L(X,Y ), and f : X → Y a given operator. Define the feasible set associated with A and K, Ω = {x ∈ D : there exists u ∈ A(x) such that 〈Q(x, u), g(y)〉 6≤intP (x) 0 ∀y ∈ D } . (3.1) We consider the following problems: 1. Generalized multivalued vector optimization problem (GMVOP)l for a given l ∈ L(X,Y ): finding x ∈ Ω such that l(x) ∈ MinwP (x) l(Ω). (3.2) 2. Generalized multivalued weak minimal element problem (GMWMEP): finding x ∈ Ω such that x ∈ MinwD Ω. 3. Generalized multivalued vector complementarity problem (GMVCP): finding x ∈ Ω, u ∈ ∈ A(x) such that 〈Q(x, u), g(x)〉 6≥intP (x) 0. 4. Generalized multivalued vector variational inequality problem (GMVVIP): finding x ∈ D and u ∈ A(x) such that 〈Q(x, u), g(y)− g(x)〉 6≤intP (x) 0 ∀y ∈ D. (3.3) 5. Generalized multivalued vector unilateral optimization problem (GMVUOP): finding x ∈ D such that f(x) ∈ MinwP (x) f(D). Definition 3.1 [3]. A linear operator l : X → Y is called weakly positive if for any x, y ∈ X, x 6≥intP y implies that l(x) 6≥intP (x) l(y). Definition 3.2. Let X and Y be the two Banach spaces, and l be a linear operator from X to Y. If the image of any bounded set in X is a self-sequentially compact set in Y then l is called completely continuous. A mapping f : X → Y is said to be convex if f(λx+ (1− λ)y) ≤P (x) λf(x) + (1− λ)f(y) (3.4) for all x, y ∈ X and 0 ≤ λ ≤ 1. Definition 3.3. Let Q : L(X,Y )→ L(X,Y ) and f : X → Y be two mappings. f is said to be Q-subdifferential at x0 ∈ X if there exists u0 ∈ L(X,Y ) such that f(x)− f(x0) ≥P (x0) 〈Q(u0), x− x0〉 ∀x ∈ X. If f is Q-subdifferentiable at x0 ∈ X, then we define the Q-subdifferential of f at x0 as follows: ∂Qf(x0) = {u ∈ L(X,Y ) : f(x)− f(x0) ≥P (x0) 〈Q(u), x− x0〉} ∀x ∈ X. If f is Q-subdifferentiable at each x ∈ X, then f is Q-subdifferential on X. ISSN 1027-3190. Укр. мат. журн., 2013, т. 65, № 1 HYBRID TYPE GENERALIZED MULTIVALUED VECTOR COMPLEMENTARITY PROBLEMS 13 Remark 3.1. We note that if X and Y are two Banach spaces, a mapping f : X → Y is Frechet differentiable at x0 ∈ X if there exists a linear bounded operator Df(x0) such that lim x→0 ‖f(x0 + x)− f(x0)− 〈Df(x0), x〉‖ ‖x‖ = 0, where Df(x0) is said to be the Frechet derivative of f at x0. The mapping f is said to be Frechet differentiable at each point of X if f : X → Y is convex and Frechet differentiable on X. Then f(y)− f(x) ≥P (x) 〈Df(x), y − x〉 ∀x, y ∈ X. If f is a Frechet differentiable on X, then for each x, y ∈ X we have f(y)− f(x) ≥P (x) 〈A(u), y − x〉 ∀y ∈ ∂Qf(x). Definition 3.4. Let X be a Banach space, D ⊂ X be a proper, closed, convex and moving pointed cone with apex at origin and intD 6= ∅. The norm ‖ · ‖ in X is called strictly monotonically increasing in D if for each y ∈ D x ∈ ({y} − intD) ∩D ⇒ ‖x‖ ≤ ‖y‖. (3.5) Theorem 3.1. Let X, Y be the two Banach spaces, D ⊂ X a proper, closed, convex moving pointed cone with apex at origin and intD 6= ∅. Let P : D → 2Y be a multivalued mapping with closed, convex moving pointed cone values such that intP (x) 6= ∅ for all x ∈ D. Suppose that 1) T = ∂Qf is the subdifferential of a convex operator f : X → Y ; 2) l is a weakly positive linear operator; 3) there exists x ∈ Ω such that Q(u) is one to one and completely continuous, where u ∈ A(x) is associated with x in the definition of Ω; 4) X is a topological dual space of a real normed space and the norm ‖ · ‖ in X is strictly monotonically increasing on D. If (GMVVIP) is solvable, then (GMVOP)l, (GMWMEP), (GMVCP) and (GMVUOP) are also solvable. We need the following proposition to prove Theorem 3.1. Proposition 3.1. Let Q : D × L(X,Y ) → L(X,Y ) and f : X → Y be the two single-valued mappings, A : D → 2L(X,Y ) be the multivalued mapping and let T = ∂Qf be the Q-subdifferential of f. Then x solves (GMVUOP) which implies that x solves (GMVVIP). If in addition, f is a convex mapping then conversely x solves (GMVVIP) which implies that x solves (GMVUOP). Proof. Let x be a solution of (GMVUOP). Then x ∈ D and f(x) ∈ MinwP (x) f(D) that is, f(x) 6≥intP (x) f(y) ∀y ∈ D. Since D is convex cone, therefore f(x) 6≥intP (x) f(x+ t(w − x)), 0 < t < 1, w ∈ D. (3.6) ISSN 1027-3190. Укр. мат. журн., 2013, т. 65, № 1 14 R. P. AGARWAL, SALAHUDDIN, M. K. AHMAD Also, since f is Q-subdifferential on X, it follows that f(x) 6≥intP (x) f(x+t(w−x)) ≥P (x) f(x)+〈Q(x, u), t(w−x)〉, 0 < t < 1, w ∈ D. (3.7) This implies that 〈Q(x, u), t(w − x)〉 6≤intP (x) 0, 0 < t < 1, w ∈ D, (3.8) and hence 〈Q(x, u), w − x〉 6≤intP (x) 0 ∀w ∈ D. (3.9) Therefore, x is the solution of (GMVVIP). Conversely, let x solve (GMVVIP). Then there exists u0 ∈ A(x) = ∂Qf(x) such that 〈Q(x, u0), w − x〉 6≤intP (x) 0 ∀w ∈ D. (3.10) Since f is Q-subdifferentiable on X, we have for all u ∈ A(x) = ∂Qf(x) f(w)− f(x) ≥P (x) 〈Q(x, u), w − x〉 ∀w ∈ D. (3.11) Since f is convex, therefore we have f(w)− f(x) ≥P (x) 〈Q(x, u0), w − x〉 6≤intP (x) 0 ∀w ∈ D. (3.12) This implies that f(w) 6≤intP (x) f(x) ∀w ∈ D. (3.13) Therefore, x solves (GMVUOP). Proposition 3.1 is proved. Proposition 3.2. If x solves (GMVVIP), then x also solves (GMVCP). Conversely, if 〈Q(x, u), g(x)〉 ≤P (x) 0 ∀w ∈ D, u ∈ A(x), then x solve (GMVCP) which implies that x solve (GMVVIP). Proof. Let x be a solution of (GMVVIP), then there exists u ∈ A(x) such that 〈Q(x, u), g(y)− g(x)〉 6≤intP (x) 0 ∀y ∈ D. (3.14) Letting y = 0, we get 〈Q(x, u), g(x)〉 6≥intP (x) 0. Since g is convex and letting y = w + x such that g(y) = g(w + x) ≤ g(w) + g(x), we have 〈Q(x, u), g(w)〉 6≤intP (x) 0 ∀w ∈ D. (3.15) Thus x is a solution of (GMVCP). ISSN 1027-3190. Укр. мат. журн., 2013, т. 65, № 1 HYBRID TYPE GENERALIZED MULTIVALUED VECTOR COMPLEMENTARITY PROBLEMS 15 Conversely, let x solve (GMVCP). Then there exists u ∈ Ax such that 〈Q(x, u), g(x)〉 ≤P (x) 0 6≥intP (x) 〈Q(x, u), g(y)〉 ∀y ∈ D. (3.16) This implies that 〈Q(x, u), g(x)〉 6≥intP (x) 〈Q(x, u), g(y)〉 ∀y ∈ D (3.17) and so 〈Q(x, u), g(y)− g(x)〉 6≥intP (x) 0 ∀y ∈ D. (3.18) Proposition 3.2 is proved. Proposition 3.3. Let l be a weakly positive linear operator. Then x solve (GMWMEP) which implies that x solve (GMVOP). Proof. Let x be a solution of (GMWMEP). Then x ∈ Ω and x ∈ MinwD Ω. That is for any z ∈ Ω, x 6≥intD z. Since l is a weakly positive linear operator, it follows that l(x) 6≥P (x) l(z) and so l(x) ∈ MinwP (x) l(Ω), (3.19) hence x solve (GMVOP). Proposition 3.3 is proved. Definition 3.5 [8]. Let X be a Banach space, D ⊂ X be a proper closed convex and moving pointed cone with apex at the origin and intD 6= ∅, N a nonempty subset of X. 1. If x ∈ X,Nx = ({x} −D) ∩N 6= ∅, then Nx is called a section of the set N. 2. N is called weakly closed if {xn} ⊂ N, x ∈ X, 〈x∗, xn〉 → 〈x∗, x〉 ∀x∗ ∈ X∗, then x ∈ N. 3. N is called bounded below if there exists a point b ∈ X such that N ⊂ b+D. Lemma 3.1 [10]. Let X be a Banach space, D ⊂ X a proper closed convex moving pointed cone with apex at the origin and intD 6= ∅, N a nonempty subset of X and X be the topological dual space of a real normed space (Z, ‖ · ‖z). Suppose there exists x ∈ X such that the section Nx is weakly closed and bounded below and the norm ‖ · ‖ in X is strictly monotonically increasing. Then the set N has at least one weakly minimal point. Lemma 3.2. If (GMVVIP) is solvable, then the feasible set Ω is nonempty. ISSN 1027-3190. Укр. мат. журн., 2013, т. 65, № 1 16 R. P. AGARWAL, SALAHUDDIN, M. K. AHMAD Proof. Let x be a solution of (GMVVIP), then there exists u ∈ A(x) such that 〈Q(x, u), g(y)− g(x)〉 6≤intP (x) 0 ∀y ∈ D. (3.20) Since g is convex, taking y = z + x with any z ∈ Ω we know that y ∈ D and 〈Q(x, u), g(z)〉 6≤intP (x) 0 ∀z ∈ D. (3.21) Thus x ∈ Ω, this completes the proof. Lemma 3.3 [3]. If the norm ‖ · ‖ in an ordered Banach space X is strictly monotonically in- creasing, then the order intervals in X are bounded. Proposition 3.4. Suppose that (GMVVIP) is solvable and 1) there exists x in Ω such that Q(x, u) is one to one and completely continuous, where u ∈ A(x) is associated with x in the definition of Ω; 2) X is the topological dual space of a real normed space (Z, ‖ · ‖Z) and the norm ‖ · ‖ in X is strictly monotonically increasing, then (GMWMEP) has at least one solution. Proof. By assumption and Lemma 3.2, Ω 6= ∅. Let x ∈ Ω be a point such that Q(x, u) is one-to-one and completely continuous where u ∈ A(x) is associated with x in the definition of Ω and let {yn} ⊂ Ω with yn → y (weakly). Since Ωx = ({x} −D) ∩ Ω ⊂ ({x} −D) ∩D = [0, x], (3.22) by Lemma 3.3. [0, x] is bounded and so is Ωx. Since Q(x, u) is completely continuous, 〈Q(x, u),Ωx〉 is a self-sequentially compact set and{ 〈Q(x, u), g(yn)〉 } ⊂ 〈Q(x, u),Ωx〉 implies that there exists a subsequence { 〈Q(x, u), g(ynk )〉 } which converges to z ∈ 〈Q(x, u),Ωx〉. We get a point y0 ∈ Ωx such that 〈Q(x, u), g(ynk )〉 → 〈Q(x, u), g(y0)〉 (strongly). (3.23) On the other hand, since yn → y, g(yn) → g(y) (weakly) and Q(x, u) is completely continuous. Then 〈Q(x, u), g(yn)〉 → 〈Q(x, u), g(y)〉 (strongly). (3.24) By the uniqueness of limits, we get 〈Q(x, u), g(y)〉 = 〈Q(x, u), g(y0)〉. Since Q(x, u) is one-to-one, y = y0 and so y ∈ Ωx. Since Ωx is weakly closed, it follows from Lemma 3.1 that Ω has a weakly minimal point b such that b 6≥intP (b) x ∀x ∈ Ω. Hence (GMWMEP) has at least one solution. Proposition 3.4 is proved. ISSN 1027-3190. Укр. мат. журн., 2013, т. 65, № 1 HYBRID TYPE GENERALIZED MULTIVALUED VECTOR COMPLEMENTARITY PROBLEMS 17 Definition 3.6. Let X, Y be the two Banach spaces, D ⊂ X a proper closed convex moving pointed cone with apex at the origin and intD 6= ∅, and P : D → 2Y a multivalued mapping with closed convex moving pointed cone such that intP (x) 6= ∅ for all x ∈ D. Let Q : D × L(X,Y )→ → L(X,Y ), g : D → D be the single-valued mappings and A : X → 2L(X,Y ) the multivalued mapping. Q is called Q-positive if 〈Q(x, u), g(y)〉 ≥P (x) 0 ∀x, y ∈ D, u ∈ A(x). (3.25) Now consider the positive generalized multivalued vector complementarity problem (PGMVCP): Finding x ∈ D and u ∈ A(x) such that 〈Q(x, u), g(y)〉 6≥intP (x) 0, 〈Q(x, u), g(y)〉 ≥P (x) 0, y ∈ D. (3.26) The feasible set related to (PGMVCP) is defined as Ω = {x ∈ D: there is u ∈ A(x) such that 〈Q(x, u), g(y)〉 ≥P (x) 0 ∀y ∈ D. (3.27) Let us consider the following problems: The generalized multivalued vector optimization problem (GMVOP)l0 : finding x ∈ Ω0 such that l(x) ∈ MinwP l(Ω0). The generalized multivalued weak minimal element problem (GMWMEP)0: finding x ∈ Ω0 such that x ∈ MinwD Ω0. The positive generalized multivalued vector complementarity problem (PGMVCP): finding x ∈ ∈ Ω0 such that 〈Q(x, u), g(x)〉 6≥intP (x) 0, (3.28) where u ∈ A(x) and Q : D × L(X,Y ) → L(X,Y ), g : D → D associated with x in the definition of Ω0. The generalized multivalued vector variational inequality problem (GMVVIP): finding x ∈ D and u ∈ A(x) such that 〈Q(x, u), g(y)− g(x)〉 6≤intP (x) 0 ∀y ∈ D. (3.29) The generalized multivalued vector unilateral optimization problem (GMVUOP): for a given mapping f : X → Y finding x ∈ D such that f(x) ∈ MinwD f(D). Definition 3.7. Let Q : D × L(X,Y )→ L(X,Y ), g : D → D be the single-valued mappings, A : D → 2L(X,Y ) be the multivalued mapping. Q is called g-strongly monotone with first variable of Q, if 〈Q(·, u)−Q(·, v), g(x)− g(y)〉 ≥P (x) 0 ∀x, y ∈ D, x 6= y, u ∈ A(x), v ∈ A(y). (3.30) ISSN 1027-3190. Укр. мат. журн., 2013, т. 65, № 1 18 R. P. AGARWAL, SALAHUDDIN, M. K. AHMAD Definition 3.8 [8]. We say that P (x) satisfies an inclusive condition if for any x, y ∈ X, x ≤intP y only implies that P (x) ⊂ P (y). (3.31) Proposition 3.5. Let Q : D × L(X,Y ) → L(X,Y ), g : D → D be the two single-valued mappings, A : X → 2L(X,Y ) be the multivalued mappings, Q is g-strongly monotone with respect to the first variable and x is a solution of (PGMVCP). If P satisfies the inclusive condition then x is a weakly minimal point of Ω0, i.e., x solve (GMWMEP)0. Proof. It is easy to see that x ∈ Ω0 ⊂ D. If x ∈ bd(D) (where bd(D) denotes the boundary of D), then x solve (GMWMEP)0, otherwise there exists x0 ∈ Ω0 such that g(x) ≥intD g(x0), g(x) = g(x− x0 + x0) ≤ g(x− x0) + g(x) ∈ intD +D ⊂ intD, which is a contradiction. If x ∈ intD, by the Q-strict monotonicity, we have 〈Q(x, u), g(x)− g(y)〉 ≥intP (x) 〈Q(x′, v′), g(x)− g(y)〉 ∀y ∈ Ω0, y 6= x, v′ ∈ A(y). Suppose g(x) ≥intD g(y). Since Q is g-positive 〈Q(x, u), g(x)− g(y)〉 ≥P (y) 0 and 〈Q(x, u), g(x)− g(y)〉 ≥intP (x) 〈Q(x, v), g(x)− g(y)〉 ≥P (x) 0. By the assumption, we get P (y) ⊂ P (x) and so 〈Q(x, u), g(x)− g(y)〉 ∈ 〈Q(x, v), g(x)− g(y)〉+ intP (x) ⊂ P (y)+ + intP (x) ⊂ P (x) + intP (x) = intP (x). It follows that 〈Q(x, u), g(x)− g(y)〉 ≥intP (x) 0, and thus 0 6≤intP (x) 〈Q(x, u), g(x)〉 ≥P (x) 〈Q(x, u), g(y)〉+ k for some k ∈ intP (x). This implies 〈Q(x, u), g(y)〉+ k 6≥intP (x) 0. Since k ∈ intP (x) and x ∈ Ω0 ISSN 1027-3190. Укр. мат. журн., 2013, т. 65, № 1 HYBRID TYPE GENERALIZED MULTIVALUED VECTOR COMPLEMENTARITY PROBLEMS 19 〈Q(x, u), g(y)〉+ k ∈ P (x) + intP (x) ⊂ intP (x) and so 〈Q(x, u), g(y)〉+ k ≥intP (x) 0, which leads to a contradiction. Therefore g(x) ≥intD g(y) does not hold, that is g(x) 6≥intD g(y) ∀y ∈ Ω0. It follows that x solve (GMWMEP)0. Proposition 3.5 is proved. Proposition 3.6. If x solve (PGMVCP), then x also solve (GMVVIP). Proof. Suppose x solve (PGMVCP). Then x ∈ D and there exists u ∈ A(x) such that 〈Q(x, u), g(x)〉 6≥intP (x) 0, 〈Q(x, u), g(y)〉 ≥P (x) 0 ∀y ∈ D. If 〈Q(x, u), g(y)− g(x)〉 ≤intP (x) 0, then 〈Q(x, u), g(x)〉 = −〈Q(x, u), g(y)− g(x)〉+ 〈Q(x, u), g(y)〉 ∈ intP (x) + P (x) ⊂ intP (x) and so 〈Q(x, u), g(x)〉 ≥intP (x) 0, which is a contradiction. It follows that 〈Q(x, u), g(y)− g(x)〉 6≤intP (x) 0, and x solve (GMVVIP). Proposition 3.6 is proved. Similarly we can obtain other equivalence condition. We have the following theorem. Theorem 3.2. Let X, Y be two Banach spaces, D ⊂ X a proper closed convex moving pointed cone with apex at the origin and intD 6= ∅ and {P (x) : x ∈ X} a family of closed moving pointed cone in Y such that intP (x) 6= ∅ for all x ∈ X. Let g : D → D, Q : D × L(X,Y ) → Y and A : X → 2L(X,Y ) be the mappings. Suppose that P satisfies the inclusive condition and 1) T = ∂Qf is the Q-subdifferential for the convex operator f : X → Y ; 2) l is a weakly positive operator; 3) A is Q-strictly monotone. 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Global Optimiz. – 2006. – 36. – P. 483 – 497. Received 29.10.12 ISSN 1027-3190. Укр. мат. журн., 2013, т. 65, № 1