On some maximum principles involving harmonic functions and their derivatives. (English) Zbl 0402.35014
MSC:
35B50 | Maximum principles in context of PDEs |
31B05 | Harmonic, subharmonic, superharmonic functions in higher dimensions |
35J15 | Second-order elliptic equations |
31B15 | Potentials and capacities, extremal length and related notions in higher dimensions |
35B05 | Oscillation, zeros of solutions, mean value theorems, etc. in context of PDEs |