(a) Show that if operators have common eigenstates they will
commute.
(b) Show also that the opposite is true too: if two operators
commute they have common eigenstates.
Show that Christoffel symbols do not transform like a tensor. And,
how does the determinant of the metric tensor transform general
under coordinate transformation?
Show that Hermitian operators have real eigenvalues. Show that
eigenvectors of a
Hermitian operator with unique eigenvalues are orthogonal. Use
Dirac notation
for this problem.
(a) Show that the diagonal entries of a positive definite matrix
are positive numbers.
(b) Show that if B is a nonsingular square matrix, then
BTB is an SPD matrix.(Hint. you simply need to show the
positive definiteness, which does requires the nonsingularity of
B.)