Operators on Complex Vector Spaces — Sheldon Axler
Mathematics — Linear Algebra · polar-decomposition
Problem
Suppose T∈L(V).
(a) Use the polar decomposition to show that there exists a unitary operator S∈L(V) such that TT∗=ST∗TS∗.
(b) Show how (a) implies that T and T∗ have the same singular values.