16.-Linear-Algebra-by-Kenneth-Hoffman · Problem 8.4.2
Inner Product Spaces
Mathematics — Linear Algebra · unitary-operators
Problem
Let V be the space of complex n×n matrices with inner product (A∣B)=tr(AB∗). For each M in V, let TM be the linear operator defined by TM(A)=MA. Show that TM is unitary if and only if M is a unitary matrix.