# Geometry and Statistics in Data Sciences, Paris

September 5, 2022 to December 9, 2022
IHP
Europe/Paris timezone
Financial support for the participation to the quarter is now closed

## Nicolas Verzelen - Optimal Permutation Estimation in Crowd-Sourcing problems

Oct 6, 2022, 11:30 AM
1h
Amphitheater Hermite, IHP

### Description

Motivated by crowd-sourcing applications, we consider a model where we have partial observations from a bivariate isotonic $n\times d$ matrix with an unknown permutation $\pi^*$ acting on its rows. We consider the twin problems of recovering the permutation $\pi^*$ and estimating the unknown matrix. We introduce a polynomial-time procedure achieving the minimax risk for these two problems, this for all possible values of $n$, $d$, and all possible sampling efforts. Along the way, we establish that, in some regimes, recovering the unknown permutation $\pi^*$ is considerably simpler than estimating the matrix. This is based on a joint work with Alexandra Carpentier (U. Potsdam) and Emmanuel Pilliat (U. Montpellier).

### Presentation materials

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