19–21 avr. 2023
Le Bois-Marie
Fuseau horaire Europe/Paris

Sketching Semidefinite Programs for Super-resolution Problems

20 avr. 2023, 16:00
30m
Le Bois-Marie

Le Bois-Marie

Centre de conférences Marylin et James Simons 35, route de Chartres 91440 Bures-sur-Yvette

Orateur

Prof. Irène Waldspurger (CNRS and Dauphine)

Description

In this talk, we will consider the canonical example of a super-resolution problem: the recovery of a measure on [0;1] from its first Fourier coefficients, assuming that the measure is the sum of a few spikes. Under weak assumptions, it is known that the measure to be recovered is the solution of a convex infinite-dimensional problem, which is in turn equivalent to a semidefinite program. This property yields a polynomial-time reconstruction algorithm with strong correctness guarantees.
Unfortunately, the size of the semidefinite program can be extremely large, even when the measure contains a very small number of spikes. I will present a sketching approach to reduce this size. Proving that this approach retains the correctness guarantees is still ongoing work. I will present a byproduct of our efforts to find proof, namely an algorithm to automatically find (simple) upper bounds on some integrals with parameters.
This work is a collaboration with Augustin Cosse and Gabriel Peyré.

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