### Nested Convex Bodies are Chaseable [chapter]

Nikhil Bansa, Martin Böhm, Marek Eliáš, Grigorios Koumoutsos, Seeun William Umboh
<span title="">2018</span> <i title="Society for Industrial and Applied Mathematics"> <a target="_blank" rel="noopener" href="https://fatcat.wiki/container/ja7dpjgz2nhjlovlil3ij5m7ei" style="color: black;">Proceedings of the Twenty-Ninth Annual ACM-SIAM Symposium on Discrete Algorithms</a> </i> &nbsp;
In the Convex Body Chasing problem, we are given an initial point v 0 ∈ R d and an online sequence of n convex bodies F 1 , . . . , F n . When we receive F i , we are required to move inside F i . Our goal is to minimize the total distance traveled. This fundamental online problem was first studied by Friedman and Linial (DCG 1993). They proved an Ω( √ d) lower bound on the competitive ratio, and conjectured that a competitive ratio depending only on d is possible. However, despite much
more &raquo; ... in the problem, the conjecture remains wide open. We consider the setting in which the convex bodies are nested: F 1 ⊃ . . . ⊃ F n . The nested setting is closely related to extending the online LP framework of Buchbinder and Naor (ESA 2005) to arbitrary linear constraints. Moreover, this setting retains much of the difficulty of the general setting and captures an essential obstacle in resolving Friedman and Linial's conjecture. In this work, we give a f (d)competitive algorithm for chasing nested convex bodies in R d .
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