Analysis of Voros criterion: what derivatives involving the logarithm of the Riemann xi-function at z=1/2 should be non-negative for the Riemann hypothesis holds true

Abstract: Recently, Voros has found the sums involving certain powers of z-1/2, which, when taken over Riemann xi-function zeroes /rho, must be positive for the Riemann hypothesis holds true and vice versa. Here we analyze these sums, write them as expressions involving only non-negative even powers of /rho-1/2, and show that the Riemann hypothesis is equivalent for the non-negativity of the derivatives (1/(2n-1)!)d^2n/dz^2n(F_(2n)(z)*ln(/xi(z))) at z=1/2 where F_(2n)=4*Sum_(k=0)^n-1((n-k)*A_(k,n)(z-1/2)^2k with the coefficients A_(k,n)=a^2k-2n*Sum_(l=k)^n(C_(2n)^2l*C_(l)^k), C_(j)^m are binomial coefficients, for any n=1, 2, 3... and any real a>1/14.