Minimization principle in study of a Stokes hemivariational inequality

In this paper, an equivalent minimization principle is established for a hemivariational inequality of the stationary Stokes equations with nonlinear slip boundary condition. Under certain assumptions on data, it shown that there unique minimizer problem, and furthermore, mixed formulation has solution. The proof result based basic knowledge convex minimization. For comparison, in existing literature, solution existence uniqueness proved through notion pseudomonotonicity application abstract surjectivity pseudomonotone operators, which additional linear growth condition required subdifferential super-potential