symmetric arrow-head matrices

Secondly we consider two kinds of the least-squares problems for inverse problems of symmetric arrow-head matrices,discuss the conditions under which they have solutions,and derive the expressions of the least-squares solutions. The corresponding algorithms are presented to compute the least-squares solutions.
3.關於問題Ⅲ,研究了一類對稱箭形矩陣逆問題有唯一解的充分必要條件,給出了求解的算法;研究了二類對稱箭形矩陣逆問題的最小二乘解,討論了問題有解的條件,竝給出了解的表達式,給出了相應的兩個計算最小二乘解的算法。