An extension of a theorem of Domar on invariant subspaces
A remarkable theorem of Domar asserts that the lattice of the invariant subspaces of the right shift semigroup {ST}r>o in L2 (R+, w(t)dt) consists of just the "standard invariant subspaces" whenever in is a positive continuous function in R+ such that (1) login is concave in [c, oo) for...
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| Dokumentumtípus: | Cikk |
| Megjelent: |
Bolyai Institute, University of Szeged
Szeged
2017
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| Sorozat: | Acta scientiarum mathematicarum
83 No. 1-2 |
| Kulcsszavak: | Matematika |
| Tárgyszavak: | |
| doi: | 10.14232/actasm-015-837-7 |
| Online Access: | http://acta.bibl.u-szeged.hu/48930 |
| Tartalmi kivonat: | A remarkable theorem of Domar asserts that the lattice of the invariant subspaces of the right shift semigroup {ST}r>o in L2 (R+, w(t)dt) consists of just the "standard invariant subspaces" whenever in is a positive continuous function in R+ such that (1) login is concave in [c, oo) for some c > 0, (2) lim^oo - l o E 4 ) = oo, and lim ^ = oo. We prove an extension of Domar's Theorem to a strictly wider class of weights w, answering a question posed by Domar in [6]. |
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| Terjedelem/Fizikai jellemzők: | 271-290 |
| ISSN: | 0001 6969 |