In the paper, we introduce the concepts of <InlineEquation ID="IEq3"> <EquationSource Format="TEX">$$G$$</EquationSource> <EquationSource Format="MATHML"> <math xmlns:xlink="http://www.w3.org/1999/xlink"> <mi>G</mi> </math> </EquationSource> </InlineEquation>-type I and generalized <InlineEquation ID="IEq4"> <EquationSource Format="TEX">$$G$$</EquationSource> <EquationSource Format="MATHML"> <math xmlns:xlink="http://www.w3.org/1999/xlink"> <mi>G</mi> </math> </EquationSource> </InlineEquation>-type I functions for a new class of nonconvex multiobjective variational control problems. For such nonconvex vector optimization problems, we prove sufficient optimality conditions for weakly...</equationsource></equationsource></inlineequation></equationsource></equationsource></inlineequation>

In this paper, we present a unified approach to computing sharp error estimates for approximate solutions of elliptic type boundary value problems in variational form. This approach is based on the duality theory of the calculus of variations which analyses the original (primal) variational...