Cone Depth and the Center Vertex Theorem
Abstract
We generalize the Tukey depth to use cones instead of halfspaces.
We prove a generalization of the Center Point Theorem that for $S\subset \reals^d$,
there is a vertex $s\in S$, with depth at least $\frac{n}{d+1}$ for cones of half-angle
$45^\circ$. This gives a notion of data depth for which an approximate median can always
be found among the original set. We present a simple algorithm for computing an
approximate center vertex.