The Nehari problem for the Hardy space on the torus

Authors
Citation
Sh. Ferguson, The Nehari problem for the Hardy space on the torus, J OPER THEO, 40(2), 1998, pp. 309-321
Citations number
10
Categorie Soggetti
Mathematics
Journal title
JOURNAL OF OPERATOR THEORY
ISSN journal
03794024 → ACNP
Volume
40
Issue
2
Year of publication
1998
Pages
309 - 321
Database
ISI
SICI code
0379-4024(199823)40:2<309:TNPFTH>2.0.ZU;2-O
Abstract
We explicitly construct functions in H-2(T-2)(perpendicular to) which deter mine bounded (big) Hankel operators on H-2(T-2) but are not of the form P(p erpendicular to)psi for any psi is an element of L-infinity(T-2). We use th is construction to show that the norm of a Hankel operator with bounded sym bol is not, in general, comparable to the distance the symbol is from H-inf inity(T-2). We also characterize the vector space quotient of symbols of bo unded Hankel operators module those which lift to L-infinity(T-2) in terms of a Toeplitz completion problem on vector-valued Hardy space in one-variab le.