“…In order to verify the theoretical assertions, we consider the following problems: where A is an n × n matrix, Π is a simple closed convex set in R n , 0 < p ∈ R n is a parameter vector. It has been shown [2] that solving problem (6.1) is equivalent to find a pair (u * , y * ), such that βf u * = A T y * (6.2) and g u * ∈ Π, g(v) − g u * T y * 0 ∀g(v) ∈ Π, (6.3)…”