- #1
Eclair_de_XII
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Homework Statement
"Let ##T## be a linear operator on a finite-dimensional vector space ##V## over an infinite field ##F##. Prove that ##T## is cyclic iff there are finitely many ##T##-invariant subspaces.
Homework Equations
T is a cyclic operator on V if: there exists a ##v\in V## such that ##\langle T,v \rangle = V##
A subspace W of V is T-invariant if: for all ##w\in W##, ##T(w)\in W##
The Attempt at a Solution
We prove the trivial case first. Suppose ##T## is a cyclic operator on ##\{0\}## the zero subspace. Then ##T(0)=0\in \{0\}##, and so, ##\langle T, 0 \rangle##. Thus, there is only one T-invariant subspace of the zero subspace.
I can't prove it the other way, though, and I'm not sure how to proceed.