Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: Function spaces

Sortuj według:

Ogranicz wyniki do:

Unbounded Hermitian operators and relative reproducing kernel Hilbert space

100%

Jorgensen P.

Open Mathematics

2010

tom 8

nr 3

569-596

We study unbounded Hermitian operators with dense domain in Hilbert space. As is known, the obstruction for a Hermitian operator to be selfadjoint or to have selfadjoint extensions is measured by a pair of deficiency indices, and associated deficiency spaces; but in practical problems, the direct computation of these indices can be difficult. Instead, in this paper we identify additional structures that throw light on the problem. We will attack the problem of computing deficiency spaces for a single Hermitian operator with dense domain in a Hilbert space which occurs in a duality relation with a second Hermitian operator, often in the same Hilbert space.

On the extent of star countable spaces

51%

Alas O., Junqueira L., Mill J., Tkachuk V., Wilson R.

Open Mathematics

2011

tom 9

nr 3

603-615

For a topological property P, we say that a space X is star Pif for every open cover Uof the space X there exists Y ⊂ X such that St(Y,U) = X and Y has P. We consider star countable and star Lindelöf spaces establishing, among other things, that there exists first countable pseudocompact spaces which are not star Lindelöf. We also describe some classes of spaces in which star countability is equivalent to countable extent and show that a star countable space with a dense σ-compact subspace can have arbitrary extent. It is proved that for any ω 1-monolithic compact space X, if C p(X)is star countable then it is Lindelöf.

Ograniczanie wyników

2 Open Mathematics

1 Alas O.

1 Jorgensen P.

1 Junqueira L.

1 Mill J.

1 Tkachuk V.

1 Wilson R.

1 2011

1 2010

Wyniki wyszukiwania

Unbounded Hermitian operators and relative reproducing kernel Hilbert space

On the extent of star countable spaces