Tuesday
45:00. Vector spaces in general
perspective on vector space as set of functions on something
Dual space
crucial point: modify notation
< $\phi$ | v >
basic idea :
can think of evaluating polynomial at a point
also, think of evaluating a fixed point on many different polynomials
these are the same numbers
objects V and V' are objects of the same kind
from this perspective, V'' is V
each v defines a functional on V'
new notation lets us see this as linear functional
Dual basis:
Lemma:
suppose have linear map from V to W
new notation is better to show the symmetry
< $\phi$ | T | v >
can go from right to left, or from left to right
in matrix form, get the transform of M(T)
video cuts out at last discussion of dual and functionals