Abstract
We consider a general equilibrium problem in a normed vector space setting and we establish sufficient conditions for the existence of solutions in compact and non compact cases. Our approach is based on the concept of upper sign property for bifunctions, which turns out to be a very weak assumption for equilibrium problems. In the framework of variational inequalities, this notion coincides with the upper sign continuity for a set-valued operator introduced by Hadjisavvas. More in general, it allows to strengthen a number of existence results for the class of relaxed \(\mu \)-quasimonotone equilibrium problems.
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References
Aussel, D., Hadjisavvas, N.: On quasimonotone variational inequalities. J. Optim. Theory Appl. 121, 445–450 (2004)
Bai, M.R., Hadjisavvas, N.: Relaxed quasimonotone operators and relaxed quasiconvex functions. J. Optim. Theory Appl. 138, 329–339 (2008)
Bai, M.R., Zhou, S.Z., Ni, G.Y.: On generalized monotonicity of variational inequalities. Comput. Math. Appl. 53, 910–917 (2007)
Baiocchi, C., Capelo, A.: Variational and Quasivariational Inequalities. Applications to Free Boundary Problems. Wiley, New York (1984)
Bigi, G., Castellani, M., Pappalardo, M., Passacantando, M.: Existence and solution methods for equilibria. Eur. J. Oper. Res., doi:10.1016/j.ejor.2012.11.037
Bianchi, M., Hadjisavvas, N., Schaible, S.: Minimal coercivity conditions for variational inequalities. Application to exceptional families of elements. J. Optim. Theory Appl. 122, 1–7 (2004)
Bianchi, M., Pini, R.: A note on stability for parametric equilibrium problems. Oper. Res. Lett. 31, 445–450 (2003)
Bianchi, M., Pini, R.: Coercivity conditions for equilibrium problems. J. Optim. Theory Appl. 124, 79–92 (2005)
Blum, E., Oettli, W.: From optimization and variational inequalities to equilibrium problems. Math. Stud. 63, 123–145 (1994)
Brézis, H., Nirenberg, L., Stampacchia, G.: A remark on Ky Fan’s minimax principle. Boll. Un. Mat. Ital. 6, 293–300 (1972)
Debrunner, H., Flor, P.: Ein Erweiterungssatz für monotone Mengen. Arch. Math. 15, 445–447 (1964)
Fan, K.: A minimax inequality and applications. In: Shisha, O. (ed.) Inequalities III, pp. 103–113. Academic Press, New York (1972)
Farajzadeh, A.P., Zafarani, J.: Equilibrium problems and variational inequalities in topological vector spaces. Optimization 59, 485–499 (2010)
Flores-Bazán, F.: Existence theorems for generalized noncoercive equilibrium problems: the quasiconvex case. SIAM J. Optim. 11, 675–690 (2000)
Giannessi, F.: On Minty variational principle. In: Giannessi, F., Komlósi, S., Rapcsák, T. (eds.) New Trends in Mathematical Programming, pp. 93–99. Kluwer, Dordrecht (1998)
García, Ramos Y., Sosa, W.: El Lema de Ky Fan y sus aplicaciones. Revista TECNIA 13(2), 75–86 (2003)
Hadjisavvas, N.: Continuity and maximality properties of pseudomonotone operators. J. Convex Anal. 10, 459–469 (2003)
Iusem, A.N., Kassay, G., Sosa, W.: On certain conditions for the existence of solutions of equilibrium problems. Math. Program. 116, 259–273 (2009)
Iusem, A.N., Sosa, W.: New existence results for equilibrium problems. Nonlinear Anal. 52, 621–635 (2003)
Karamardian, S.: Strictly quasi-convex (concave) functions and duality in mathematical programming. J. Math. Anal. Appl. 20, 344–358 (1967)
Knaster, B., Kuratowski, C., Mazurkiewicz, S.: Ein Beweies des Fixpunktsatzes für \(N\) Dimensionale Simplexe. Fund. Math. 14, 132–137 (1929)
Konnov, I.V.: Partial proximal point method for nonmonotone equilibrium problems. Optim. Methods Softw. 21, 373–384 (2006)
Luc, D.T.: Existence results for densely pseudomonotone variational inequalities. J. Math. Anal. Appl. 254, 291–308 (2001)
Minty, G.J.: On the generalization of a direct method of the calculus of variations. Bull. Am. Math. Soc. 73, 315–321 (1967)
Nikaido, H., Isoda, K.: Note on noncooperative convex games. Pac. J. Math. 5, 807–815 (1955)
Nirenberg, L.: Topics in Nonlinear Functional Analysis. New York University Press, New York (1974)
Ortega, J.M., Rheinboldt, W.C.: Iterative Solution of Nonlinear Equations in Several Variables. Academic Press, New York (1970)
Zukhovitskii, S.I., Polyak, R.A., Primak, M.E.: On an \(n\)-person concave game and a production model. Sov. Math. Dokl. 11, 522–526 (1970)
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Castellani, M., Giuli, M. Refinements of existence results for relaxed quasimonotone equilibrium problems. J Glob Optim 57, 1213–1227 (2013). https://doi.org/10.1007/s10898-012-0021-2
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DOI: https://doi.org/10.1007/s10898-012-0021-2