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arXiv · 1805.03277

On quasinilpotent operators and the invariant subspace problem

Adi Tcaciuc
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Abstract

We show that a bounded quasinilpotent operator $T$ acting on an infinite dimensional Banach space has an invariant subspace if and only if there exists a rank one operator $F$ and a scalar $α\in\mathbb{C}$, $α\neq 0$, $α\neq 1$, such that $T+F$ and $T+αF$ are also quasinilpotent. We also prove that for any fixed rank-one operator $F$, almost all perturbations $T+αF$ have invariant subspaces of infinite dimension and codimension.

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Adi Tcaciuc. 2019-11-14. On quasinilpotent operators and the invariant subspace problem. https://doi.org/10.1016/j.jmaa.2019.04.026

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