Analytic functions Approximation theory Complexe variabelen Functies (wiskunde) Machtreeksen Potentiaaltheorie Analytische Funktion Approximation, Théorie de l' Elliptic equations and systems Equations of mathematical physics and other areas of application Fonctions analytiques Functions of a Complex Variable Functions of complex variables General topics Higher-dimensional theory Higher-order elliptic equations Inequalities (Mathematics) Inequalities involving derivatives and differential and integral operators, inequalities for integrals Integral representations, integral operators, integral equations methods Komplexe Funktion MATHEMATICS Maximum principles Maximum principles (Mathematics) PDEs in connection with fluid mechanics PDEs in connection with mechanics of deformable solids Parabolic equations and systems Partial differential equations Partial differential equations -- Elliptic equations and systems -- Higher-order elliptic equations Partial differential equations -- Elliptic equations and systems -- Second-order elliptic systems Partial differential equations -- Equations of mathematical physics and other areas of application -- PDEs in connection with fluid mechanics