解析学火曜セミナー

過去の記録 ~07/24次回の予定今後の予定 07/25~

開催情報 火曜日 16:00~17:30 数理科学研究科棟(駒場) 156号室
担当者 石毛 和弘, 坂井 秀隆, 伊藤 健一
セミナーURL https://www.ms.u-tokyo.ac.jp/seminar/analysis/

2013年11月19日(火)

16:30-18:00   数理科学研究科棟(駒場) 128号室
Alexander Pushnitski 氏 (King's Colledge London)
Inverse spectral problem for positive Hankel operators (ENGLISH)
[ 講演概要 ]
Hankel operators are given by (infinite) matrices with entries
$a_{n+m}$ in $\\ell^2$. We consider inverse spectral problem
for bounded self-adjoint positive Hankel operators.
A famous theorem due to Megretskii, Peller and Treil asserts
that such operators may have any continuous spectrum of
multiplicity one or two and any set of eigenvalues of multiplicity
one. However, more detailed questions of inverse spectral
problem, such as the description of isospectral sets, have never
been addressed. In this talk I will describe in detail the
direct and inverse spectral problem for a particular sub-class
of positive Hankel operators. The talk is based on joint work
with Patrick Gerard (Paris, Orsay).