Several Inverse M-matrix Hadamard Product Closed

In this thesis, we mainly investigate the Hadamard product for some special types of inverse M-matrices, and give a simple answer to the question of Charles R. Johnson.The thesis consists of three chapters. The first chapter is Introduction, in which we introduct some related definitions and notations.In Chapter 2, the Hadamard product for some special types of inverse M-matrices is considered. We found some special types of inverse M-matrices which are closed under Hadamard product for the order n, tridiagonal inverse M-matrices and five-diagonal inverse M-matrices included.In Chapter 3,we make a further study on the question of Charles R. Johnson.