Maximum permanent and Hermitian matrices Original Research Article

Drew and Johnson obtained an expression for max{per A}, where A runs through all 3-by-3 real symmetric positive semidefinite matrices with the given eigenvalues λ1, λ2, λ3, and conjectured that the expression can be extended to include hermitian matrices. We prove that their conjecture is correct and characterize a 3-by-3 positive semidefinite hermitian matrix B, whose permanent is max{P3(D)}.