The \((S)_+\)-condition for vector equilibrium problems (Q2493608)

The author generalizes some conditions to bifunctions with values in an ordered Hausdorff topological vector space and defines a weak condition for bifunctions. These conditions extend naturally to operators from nonempty subsets of a topological vector space into the set \(L(X,Z)\) of all continuous linear mappings from \(X\) into \(Z\). Then some existence results are derived for equilibrium problems.