2019
Том 71
№ 11

All Issues

Neidhardt H.

Articles: 1
Article (English)

New aspects of Krein's extension theory

Brasche J. F., Koshmanenko V. D., Neidhardt H.

↓ Abstract   |   Full text (.pdf)

Ukr. Mat. Zh. - 1994. - 46, № 1-2. - pp. 37–54

The extension problem for closed symmetric operators with a gap is studied. A new kind of parametrization of extensions (the so-called Krein model) is developed. The notion of a singular operator plays the key role in our approach. We give the explicit description of extensions and establish the spectral properties of extended operators.