Fโก(a,bc;z)โขFโก(โˆ’a,โˆ’bโˆ’c;z)+aโขbโข(aโˆ’c)โข(bโˆ’c)c2โข(1โˆ’c2)โขz2โขFโก(1+a,1+b2+c;z)โขFโก(1โˆ’a,1โˆ’b2โˆ’c;z)=1.