Existence results for equilibrium problems under strong sign property

Abstract

This paper concerns equilibrium problems in real metric linear spaces. Considering a modified notion of upper sign property for bifunctions, we obtain the relationship between the solution sets of the local Minty equilibrium problem and the equilibrium problem, where the technical conditions on $f$ used in the literature are relaxed. The KKM technique is used to generalize and unify some existence results for the relaxed $mu$-quasimonotone equilibrium problems in the literature.