Abstract
In this paper, existence results for scalar and vector equilibrium problems involving two bifunctions are established. To this aim, a new concept of generalized pseudomonotonicity for a pair of bifunctions is introduced. It leads to existence criteria different from the ones encountered in the literature. The given applications refer to minimax inequalities and variational inequality problems.
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Alleche, B., Rădulescu, V.: Solutions and approximate solutions of quasi-equilibrium problems in Banach spaces. J. Optim. Theory Appl. 170, 629–649 (2016)
Alleche, B., Rădulescu, V.: Set-valued equilibrium problems with applications to Browder variational inclusions and to fixed point theory. Nonlinear Anal. Real World Appl. 28, 251–268 (2016)
Aliprantis, C.D., Border, K.C.: Infinite dimensional analysis. A hitchhiker’s guide. Springer, Berlin (2006)
Ansari, Q.H., Köbis, E., Yao, J.C.: Vector variational inequalities and vector optimization. In: Jahn, J. (ed.) Theory and applications. Vector Optimization. Springer, Berlin (2018)
Balaj, M.: Stampacchia variational inequality with weak convex mappings. Optimization 67, 1571–1577 (2018)
Balaj, M.: Existence results for quasi-equilibrium problems under a weaker equilibrium condition. Oper. Res. Lett. 49, 333–337 (2021)
Barbu, V., Precupanu, T.: Convexity and optimization in banach spaces. D. Reidel, Dordrecht, The Netherlands (1986)
Berge, C.: Topological spaces. Including a treatment of multi-valued functions, vector spaces and convexity. Dover Publications, Inc., Mineola, NY (1997)
Bianchi, M., Hadjisavvas, N., Schaible, S.: Vector equilibrium problems with generalized monotone bifunctions. J. Optim. Theory Appl. 92, 527–542 (1997)
Bianchi, M., Pini, R.: A note on equilibrium problems with properly quasimonotone bifunctions. J. Global Optim. 20, 67–76 (2001)
Bianchi, M., Pini, R.: Coercivity conditions for equilibrium problems. J. Optim. Theory Appl. 124, 79–92 (2005)
Bianchi, M., Schaible, S.: Generalized monotone bifunctions and equilibrium problems. J. Optim. Theory Appl. 90, 31–43 (1996)
Blum, E., Oettli, W.: From optimization and variational inequalities to equilibrium problems. Math. Student 63, 123–145 (1994)
Castellani, M., Giuli, M.: On equivalent equilibrium problems. J. Optim. Theory Appl. 147, 157–168 (2010)
Cotrina, J., Zúñiga, J.: Quasi-equilibrium problems with non-self constraint map. J. Global Optim. 75, 177–197 (2019)
Cotrina, J., Svensson, A.: The finite intersection property for equilibrium problems. J. Global Optim. 79, 941–957 (2021)
Daniilidis, A., Hadjisavvas, N.: Existence theorems for vector variational inequalities. Bull. Austral. Math. Soc. 54, 473–481 (1996)
Ding, X.P., Tan, K.K.: A minimax inequality with applications to existence of equilibrium point and fixed point theorems. Colloq. Math. 63, 233–247 (1992)
Engelking, R.: General Topology, 2nd edn. HeldermanVerlag, Berlin (1989)
Fakhar, M., Zafarani, J.: Equilibrium problems in the quasimonotone case. J. Optim. Theory Appl. 126, 125–136 (2005)
Fan, K.: A generalization of Tychonoff’s fixed point theorem. Math. Ann. 142, 305–310 (1960/61)
Giannessi, F.: Theorems of alternative, quadratic programs and complementarity problems. In: Variational inequalities and complementarity problems (Proc. Internat. School, Erice, 1978), pp. 151-186. Wiley, Chichester (1980)
Hadjisavvas, N., Schaible, S.: From scalar to vector equilibrium problems in the quasimonotone case. J. Optim. Theory Appl. 96, 297–309 (1998)
Iusem, A.N., Kassay, G., Sosa, W.: An existence result for equilibrium problems with some surjectivity consequences. J. Convex Anal. 16, 807–826 (2009)
Iusem, A.N., Kassay, G., Sosa, W.: On certain conditions for the existence of solutions of equilibrium problems. Math. Program. 116, 259–273 (2009)
Jeyakumar, V., Oettli, W., Natividad, M.: A solvability theorem for a class of quasiconvex mappings with applications to optimization. J. Math. Anal. Appl. 179, 537–546 (1993)
Kelley, J.L.: General topology. Van Nostrand, New York (1955)
Kneser, H.: Sur un théorème fondamental de la théorie des jeux. C. R. Acad. Sci. Paris 234, 2418–2420 (1952)
Konnov, I.V., Yao, J.C.: On the generalized vector variational inequality problem. J. Math. Anal. Appl. 206, 42–58 (1997)
Muu, L.D., Oettli, W.: Convergence of an adaptive penalty scheme for finding constrained equilibria. Nonlinear Anal. 18, 1159–1166 (1992)
Nasri, M., Sosa, W.: Equilibrium problems and generalized Nash games. Optimization 60, 1161–1170 (2011)
Nikaidô, H.: Isoda, K: note on non-cooperative convex games. Pacific J. Math. 5, 807–815 (1955)
Oettli, W.: A remark on vector-valued equilibria and generalized monotonicity. Acta Math. Vietnam. 22, 213–221 (1997)
Palais, R.S.: When proper maps are closed. Proc. Amer. Math. Soc. 24, 835–836 (1970)
Tan, K.K., Yuan, Z.: A minimax inequality with applications to existence of equilibrium points. Bull. Austral. Math. Soc. 47, 483–503 (1993)
Terkelsen, F.: Some minimax theorems. Math. Scand. 31, 405–413 (1972)
Whyburn, G.T.: Directed families of sets and closedness of functions. Proc. Nat. Acad. Sci. U.S.A. 54, 688–692 (1965)
Yao, J.C.: Multi-valued variational inequalities with K-pseudomonotone operators. J. Optim. Theory Appl. 83, 391–403 (1994)
Yen, C.L.: A minimax inequality and its applications to variational inequalities. Pacific J. Math. 97, 477–481 (1981)
Zhou, J., Chen, G.: Diagonal convexity conditions for problems in convex analysis and quasi-variational inequalities. J. Math. Anal. Appl. 132, 213–225 (1988)
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Balaj, M. Scalar and vector equilibrium problems with pairs of bifunctions. J Glob Optim 84, 739–753 (2022). https://doi.org/10.1007/s10898-022-01159-7
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DOI: https://doi.org/10.1007/s10898-022-01159-7