On the Result of Killip, Molchanov, and Safronov
نویسنده
چکیده
We study the properties of operators (−∆) ± V . We discuss a recent result of Killip, Molchanov, and Safronov [4] which states that if the negative spectra of these operators are discrete, then their positive spectra do not have gaps. Similar statements are also proved for more general operators of the form α(i∇) ± V and operators on the lattice Z. Here, we give a more detailed description of the matter. Notations. For an open domain Ω ⊂ R, the symbol H(Ω) denotes the Sobolev space of functions u : Ω 7→ C satisfying the condition ||u||2Hl = ∫
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