Normal/unitary/Hermitian linear operator and its representation matrix lemma
Polar norm equations lemma
Normal linear operator criterion theorem
Unitary linear operator criterion theorem
Unitary linear operator and angles lemma
Examples of unitary operators
Operations preserving matrix unitarity lemma
Unitary matrix and its row/column spaces lemma
Following lemmas are also correct for matrices under standard inner product
Normality after addition with scalar linear operator lemma
Eigenvalues of adjoint linear operator lemma
Orthogonality of eigenvectors of normal linear operator lemma
Unitary linear operator eigenvalues lemma