• Corpus ID: 226976097

Jensen's inequality in geodesic spaces with lower bounded curvature

@article{Paris2020JensensII,
  title={Jensen's inequality in geodesic spaces with lower bounded curvature},
  author={Quentin Paris},
  journal={arXiv: Metric Geometry},
  year={2020}
}
  • Q. Paris
  • Published 17 November 2020
  • Mathematics
  • arXiv: Metric Geometry
Let $(M,d)$ be a separable and complete geodesic space with curvature lower bounded, by $\kappa\in \mathbb R$, in the sense of Alexandrov. Let $\mu$ be a Borel probability measure on $M$, such that $\mu\in\mathcal P_2(M)$, and that has at least one barycenter $x^{*}\in M$. We show that for any geodesically $\alpha$-convex function $f:M\to \mathbb R$, for $\alpha\in \mathbb R$, the inequality \[f(x^*)\le \int_M (f -\frac{\alpha}{2}d^2(x^*,.))\,{\rm d}\mu,\] holds provided $f$ is locally… 
1 Citations
Online learning with exponential weights in metric spaces
  • Q. Paris
  • Mathematics, Computer Science
    ArXiv
  • 2021
TLDR
This paper extends the analysis of the exponentially weighted average forecaster, traditionally studied in a Euclidean settings, to a more abstract framework using the notion of barycenters, a suitable version of Jensen’s inequality and a synthetic notion of lower curvature bound in metric spaces known as the measure contraction property.

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