## Seminars and Colloquia by Series

### A complex analytic approach to mixed spectral problems

Series
Analysis Seminar
Time
Wednesday, September 18, 2019 - 13:55 for 1 hour (actually 50 minutes)
Location
Speaker
Burak HatinoğluTexas A&amp;M

This talk is about an application of complex function theory to inverse spectral problems for differential operators. We consider the Schroedinger operator on a finite interval with an L^1-potential. Borg's two spectra theorem says that the potential can be uniquely recovered from two spectra. By another classical result of Marchenko, the potential can be uniquely recovered from the spectral measure or Weyl m-function. After a brief review of inverse spectral theory of one dimensional regular Schroedinger operators, we will discuss complex analytic methods for the following problem: Can one spectrum together with subsets of another spectrum and norming constants recover the potential?

### \ell^p improving and sparse inequalities for averages along the square integers

Series
Analysis Seminar
Time
Wednesday, September 11, 2019 - 13:55 for 1 hour (actually 50 minutes)
Location
Skiles 005
Speaker
Rui HanGeorgia Tech

Let $f$ be defined on $\mathbb{Z}$. Let $A_N f$ be the average of $f$ along the square integers.

### Schur multipliers in perturbation theory

Series
Analysis Seminar
Time
Wednesday, February 27, 2019 - 13:55 for 1 hour (actually 50 minutes)
Location
Skiles 005
Speaker
Anna SkripkaUniversity of New Mexico
Linear Schur multipliers, which act on matrices by entrywisemultiplications, as well as their generalizations have been studiedfor over a century and successfully applied in perturbation theory. Inthis talk, we will discuss extensions of Schur multipliers tomultilinear infinite dimensional transformations and then look intoapplications of the latter to approximation of operator functions.