Nekrasov matrix

In mathematics, a Nekrasov matrix or generalised Nekrasov matrix is a type of diagonally dominant matrix (i.e. one in which the diagonal elements are in some way greater than some function of the non-diagonal elements). Specifically if A is a generalised Nekrasov matrix, its diagonal elements are non-zero and the diagonal elements also satisfy, $a_{ii}>R_i(A)$ where, $R_i(A)=\sum _{j=1}^{i-1}|a_{ij}|\frac{R_j(A)}{|a_{jj}|}+\sum _{j=i+1}^n|a_{ij}|$.