An error bound for the USAOR method

Suppose Ax=bAx=b is a system of linear equations where the matrix A   is symmetric positive definite and consistently ordered. A bound for the norm of the error ɛk=x-xkɛk=x-xk of the USAOR method in terms of the norms of δk=xk-xk-1δk=xk-xk-1 and δk+1=xk+1-xkδk+1=xk+1-xk and their inner product are derived.