×

On Krein-von Neumann and Friedrichs extensions. (English) Zbl 1050.47011

Summary: We give domain and range characterization of the smallest (Krein-von Neumann) positive self-adjoint extension of Hilbert space operators. We give new proofs of these facts for the largest (Friedrichs) extension as well. Boundedly or compactly invertible extremal extensions are also characterized as an application.

MSC:

47A20 Dilations, extensions, compressions of linear operators
47B25 Linear symmetric and selfadjoint operators (unbounded)
PDF BibTeX XML Cite