Abstract
The set of all nonnegative self-adjoint extensions of a nonnegative linear relation (multi-valued linear operator) is described by using a partial order defined on the set of the corresponding quadratic forms. This characterization leads to a generalization of a result due to M.G. Kreĭn.
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Sandovici, A. (2008). On a Kreĭn Criterion. In: Behrndt, J., Förster, KH., Langer, H., Trunk, C. (eds) Spectral Theory in Inner Product Spaces and Applications. Operator Theory: Advances and Applications, vol 188. Birkhäuser Basel. https://doi.org/10.1007/978-3-7643-8911-6_12
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DOI: https://doi.org/10.1007/978-3-7643-8911-6_12
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