6Endomorphisms
IB Linear Algebra
6 Endomorphisms
Endomorphisms are linear maps from a vector space
V
to itself. One might
wonder — why would we want to study these linear maps in particular, when
we can just work with arbitrary linear maps from any space to any other space?
When we work with arbitrary linear maps, we are free to choose any basis
for the domain, and any basis for the co-domain, since it doesn’t make sense to
require they have the “same” basis. Then we proved that by choosing the right
bases, we can put matrices into a nice form with only 1’s in the diagonal.
However, when working with endomorphisms, we can require ourselves to use
the same basis for the domain and co-domain, and there is much more we can
say. One major objective is to classify all matrices up to similarity, where two
matrices are similar if they represent the same endomorphism under different
bases.