Thickness and Antithickness of Graphs
arXiv:1708.04773 · doi:10.20382/jocg.v9i1a12
Abstract
This paper studies questions about duality between crossings and non-crossings in graph drawings via the notions of thickness and antithickness. The "thickness" of a graph is the minimum integer such that in some drawing of , the edges can be partitioned into noncrossing subgraphs. The "antithickness" of a graph is the minimum integer such that in some drawing of , the edges can be partitioned into thrackles, where a "thrackle" is a set of edges, each pair of which intersect exactly once. (Here edges with a common endvertex are considered to intersect at .) So thickness is a measure of how close a graph is to being planar, whereas antithickness is a measure of how close a graph is to being a thrackle. This paper explores the relationship between the thickness and antithickness of a graph, under various graph drawing models, with an emphasis on extremal questions.