This paper is mainly concerned with solving the following two problems:
Problem Ⅰ.Given X ∈Cn×m,(A)=diag(λ1,λ2…,λm)∈Cm×m.Find A∈ABSRn×n such that
AX = XA
where ABSRn×n is the set of all real n × n anti-bisymmetric matrices.
Problem Ⅱ. Given A* ∈ Rn×n. Find (A^) ∈ SE such that
‖A*-(A^)‖F=min A∈SE‖A*-A‖F,
where ‖ @ ‖F is Frobenius norm, and SE denotes the solution set of Problem I.The necessary and sufficient conditions for the solvability of Problem Ⅰ have been stud-ied. The general form of SE has been given. For Problem Ⅱ the expression of the solutionhas been provided.