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Keywords:
Hyponormal operators; Krein spaces; $J$-hyponormal operators
Hyponormal operators; Krein spaces; $J$-hyponormal operators
Summary:
In this paper the hyponormal operators on Krein spaces are introduced. We state conditions for the hyponormality of bounded operators focusing, in particular, on those operators $T$ for which there exists a fundamental decomposition $\mathbb{K}= \mathbb{K}^{+} \oplus \mathbb{K}^{-}$ of the Krein space $\mathbb{K}$ with $\mathbb{K}^{+}$ and $\mathbb{K}^{-}$ invariant under $T$.
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