Ky Fan inequality for marginally 0-lower semicontinuous bifunctions
DOI:
https://doi.org/10.12775/TMNA.2026.011Keywords
Ky Fan inequality, equilibrium problem, marginal $r$-lower semicontinuity, two-function minimax inequality, variational inequalityAbstract
The aim of this paper is twofold. First, we introduce the notion of bifunction marginally $r$-lower semicontinuous in the second variable. Then, for such bifunctions, we establish theorems regarding the existence of solutions for the Ky Fan inequality problem. As we will see, our results prove to be useful in certain cases where other existence theorems from the literature are not applicable. As applications, a two-bifunction minimax inequality and an existence theorem for the Stampacchia variational inequality problem are established.References
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