New Harnack inequalities and existence theorems for radially symmetric solutions of elliptic PDEs with sign changing or vanishing Green's function
Keywords: معادله انتگرال Hammerstein; primary; 35B09; 35J25; 45G10; 45M20; secondary; 34B10; 34B18; 47A10; 47H14; 47H30; Radially symmetric solution; Hammerstein integral equation; Nonlocal boundary condition; Sign-changing Green's function; Vanishing Green's function;