Paper 2, Section II, F

Linear Algebra
Part IB, 2012

(i) Define the transpose of a matrix. If VV and WW are finite-dimensional real vector spaces, define the dual of a linear map T:VWT: V \rightarrow W. How are these two notions related?

Now suppose VV and WW are finite-dimensional inner product spaces. Use the inner product on VV to define a linear map VVV \rightarrow V^{*} and show that it is an isomorphism. Define the adjoint of a linear map T:VWT: V \rightarrow W. How are the adjoint of TT and its dual related? If AA is a matrix representing TT, under what conditions is the adjoint of TT represented by the transpose of AA ?

(ii) Let V=C[0,1]V=C[0,1] be the vector space of continuous real-valued functions on [0,1][0,1], equipped with the inner product

f,g=01f(t)g(t)dt\langle f, g\rangle=\int_{0}^{1} f(t) g(t) d t

Let T:VVT: V \rightarrow V be the linear map

Tf(t)=0tf(s)dsT f(t)=\int_{0}^{t} f(s) d s

What is the adjoint of T?T ?