Contraction and uniform convergence of isotonic regression

Fan Yang; Rina Foygel Barber

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arXiv · 1706.01852

Contraction and uniform convergence of isotonic regression

Fan Yang·Rina Foygel Barber

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Abstract

We consider the problem of isotonic regression, where the underlying signal $x$ is assumed to satisfy a monotonicity constraint, that is, $x$ lies in the cone $\{ x\in\mathbb{R}^n : x_1 \leq \dots \leq x_n\}$. We study the isotonic projection operator (projection to this cone), and find a necessary and sufficient condition characterizing all norms with respect to which this projection is contractive. This enables a simple and non-asymptotic analysis of the convergence properties of isotonic regression, yielding uniform confidence bands that adapt to the local Lipschitz properties of the signal.

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Fan Yang, Rina Foygel Barber. 2017-06-06. Contraction and uniform convergence of isotonic regression. https://arxiv.org/abs/1706.01852

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