Title: A generalization of crossing families,
Abstract: For a set of points in the plane, a \emph{crossing family} is a set of line
segments, each joining two of the points, such that any two line segments
cross. We investigate the following generalization of crossing families: a
\emph{spoke set} is a set of lines drawn through a point set such that each
unbounded region of the induced line arrangement contains at least one point of
the point set. We show that every point set has a spoke set of size
$\sqrt{\frac{n}{8}}$. We also characterize the matchings obtained by selecting
exactly one point in each unbounded region and connecting every such point to
the point in the antipodal unbounded region.