Let P ∈ ORn×n such that PT = P, and Where is the set of all n × n symmetric ortho-symmetric matrices. In this paper, we discuss the following problems: Problem I0. Given A = diag, diag and let Y = ZΛ. in S. Find A ∈S such that AX = XΓ. Problem Ⅰ. Given X,B ∈ Rn×m. Find A∈S such that ||AX-B|| = min. Problem Ⅱ. Given A ∈ Rn×n. Find .A* ∈ SE such that Where ||·|| is the Frobenius norm, and SE is the solution set of Problem Ⅰ. In this paper the general representation of SE has been given. The necessary and sufficient conditions have...