Convex hulls of perturbed random point sets - Archive ouverte HAL
Article Dans Une Revue The Annals of Applied Probability Année : 2021

Convex hulls of perturbed random point sets

Pierre Calka
J. E. Yukich
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Résumé

We consider the convex hull of the perturbed point process comprised of $n$ i.i.d. points, each distributed as the sum of a uniform point on the unit sphere $\S^{d-1}$ and a uniform point in the $d$-dimensional ball centered at the origin and of radius $n^{\alpha}, \alpha \in (-\infty, \infty)$. This model, inspired by the smoothed complexity analysis introduced in computational geometry \cite{DGGT,ST}, is a perturbation of the classical random polytope. We show that the perturbed point process, after rescaling, converges in the scaling limit to one of five Poisson point processes according to whether $\alpha$ belongs to one of five regimes. The intensity measure of the limit Poisson point process undergoes a transition at the values $\alpha = \frac{-2} {d -1}$ and $\alpha = \frac{2} {d + 1}$ and it gives rise to four rescalings for the $k$-face functional on perturbed data. These rescalings are used to establish explicit expectation asymptotics for the number of $k$-dimensional faces of the convex hull of either perturbed binomial or Poisson data. In the case of Poisson input, we establish explicit variance asymptotics and a central limit theorem for the number of $k$-dimensional faces. Finally it is shown that the rescaled boundary of the convex hull of the perturbed point process converges to the boundary of a parabolic hull process.

Dates et versions

hal-02423605 , version 1 (24-12-2019)

Identifiants

Citer

Pierre Calka, J. E. Yukich. Convex hulls of perturbed random point sets. The Annals of Applied Probability, 2021, 31, pp.1598-1632. ⟨10.1214/20-AAP1627⟩. ⟨hal-02423605⟩
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