3 problems

The uncrossed number of a graph is the minimum number of planar drawings in an uncrossed collection whose union contains every edge of the graph. Here, $NP$ denotes nondeterministi…

Let $d$ be a prescribed thickness, and consider convex bodies in three-dimensional space with thickness $d$. The Heil body is the convex hull of six circular arcs of radius $d$, ce…

For a graph, geometric thickness is the minimum number of plane geometric layers in a straight-line drawing, and geometric antithickness is the minimum number of geometric thrackle…