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##

Invariant Subspaces

An *invariant subspace*
of satisfies for all .
We also write this as
.
The simplest example is when is spanned by a single eigenvector of .
More generally any invariant subspace can be spanned by a subset of
the eigenvectors of , although the vectors spanning do not have to
be eigenvectors themselves.

Susan Blackford
2000-11-20