On subharmonic functions
On subharmonic functions
If p(x, y) is continuous in a domain (non-null connected open set) D, then p(x, y) is subharmonic in D if and only if the inequality p(x, y) g A(p; x, y; r) ss --I J p(x + £, y + rj)d^drj TT 2 J J D(x,y\r) holds for all …