Let H be a complex Hilbert space. 6. (a) Let φ, ψ E H \ {0} . Define the linear operator T on H by Using the Cauchy...
Problem 3. (1) Let H be a Hilbert space and S, TE B(HH). Then, prove that ||ST|| ||||||||| (2) Let X, Y be Hilbert spaces and Te B(X,Y). Then, prove that ||1||| sup ||T3|1 TEX=1 Let X, Y be Banach spaces. Definition (review) We denote by B(X, Y) a set of all bounded linear operators T:X + Y with D(T) = X. B(X, Y) is a vector space. Definition (review) A linear operator T:X + Y is said to be...
Let H be a separable Hilbert space with basis en]nen and define P as the orthogonal projection onto span(e,... ,en) (a) A sequence of operators T, E B(H) is said to converge strongly to T if |Th-Tnhl converges to 0 for all h EH (note that strong convergence is actually weaker than operator norm convergence-think of this as the difference between pointwise and uniform convergence). Show that, for any T E B(H), the sequence P,T Pn converges strongly to T....
Let A be an invertible linear operator on a finite-dimensional complex vector space V. Recall that we have shown in class that in this case, there exists a unique unitary operator U such that A=UA. The point of this exercise is to prove the following result: an invertible operator A is normal if and only if U|A= |AU. a) Show that if UA = |A|U, then AA* = A*A. Now, we want to show the other direction, i.e. if AA*...