#### İstanbul Analysis Seminars

Beurling-type invariant subspaces in the polydisc
Beyaz Başak Koca
İstanbul University, Turkey
Özet : It is well-known, by Beurling’s theorem, that all invariant subspaces for the multiplication operator by the independent variable on the Hardy space $H^2(\mathbb{D})$ in the unit disk are of Beurling-type, i.e., they are of the form $fH^2(\mathbb{D})$, where $f$ is an inner function in $H^2(\mathbb{D})$. However, the structure of the invariant subspaces of the Hardy space in the polydisc cannot be characterized in such a simple form. Although it is quite clear that the Beurlingtype subspaces are invariant, it is known that not all invariant subspaces are of this form. In this talk, we will characterize the Beurling-type invariant subspaces of the Hardy space in the polydisc by using the classical Lax−Halmos Theorem.
 Tarih : 26.02.2016 Saat : 15:40 Yer : Sabancı University, Karaköy Communication Center, Bankalar Caddesi 2, Karaköy Dil : English