Linear Algebra Done Right · Problem 7D.13

Operators on Inner Product Spaces — Sheldon Axler

Mathematics — Linear Algebra · isometries-unitary-operators

Problem

Explain why the columns of a square matrix of complex numbers form an orthonormal list in

\mathbf{C}^n

if and only if the rows of the matrix form an orthonormal list in

\mathbf{C}^n