Composition operators on Hardy spaces on Lavrentiev domains
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Autores: Eva Antonia Gallardo Gutiérrez
, Artur Nicolau Nos , M.J. González
- Localización: Pre-publicaciones del Seminario Matemático " García de Galdeano ", Nº. 10, 2006
- Idioma: inglés
- Enlaces
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Resumen
For any simply connected domain , we prove that a Little- wood type inequality is necessary for boundedness of composition operators on Hp( ), 1 p < 1, whenever the symbols are finitely-valent. Moreover, the corresponding ¿little-oh¿ condition is also necessary for the compactness. Nevertheless, it is shown that such inequality is not sufficient for characterizing bounded composition operators even induced by univalent symbols. Further- more, such inequality is no longer necessary if we drop the extra assumption on the symbol of being finitely-valent. In particular, this solves a question posed by Shapiro and Smith [12]. Finally, we show a striking link between the geometry of the underlying domain and the symbol inducing the composi- tion operator in Hp( ), and in this sense, we relate both facts characterizing bounded and compact composition operators whenever is a Lavrentiev do- main.
