On the continuity of the kernel of invex functions
A differentiable real function is invex on a domain \(C\) if \(f(x)- f(u) \geq\eta(x,u)^T \nabla f(u)\) for all \(x,u\) in \(C\). Examples are given where the kernel \(\eta(.,.)\) is required to be continuous; and sufficient conditions are obtained for a continuous \(\eta\) to exist, or to not exist.
scientific article; zbMATH DE number 902458