The spatial arrangement of social network data in graphs can influence viewers" perceptions of structural characteristics such as prominence, bridging and grouping. To study the extent of this effect, we conducted an experiment with 80 graduate students. Each student viewed three of five different spatial arrangements of the same network. We found that viewers' perceptions of structural feature...

The spatial arrangement of social network data in graphs can influence viewers’ perceptions of structural characteristics such as prominence, bridging and grouping. To study the extent of this effect, we conducted an experiment with 80 graduate students. Each student viewed three of five different spatial arrangements of the same network. We found that viewers' perceptions of structural feature...

Introduction. A pseudoline is formed from a line by stretching the plane without tearing: it is the image of a line under a homeomorphism of the plane [13]. In arrangements of pseudolines, pairs of pseudolines intersect at most once and cross at their intersections. Pseudoline arrangements can be used to model sorting networks [1], tilings of convex polygons by rhombi [4], and graphs that have ...

We generalize the Hadwiger theorem on line transversals to collections of compact convex sets in the plane to the case where the sets are connected and the transversals form an arrangement of pseudolines. The proof uses the embeddability of pseudoline arrangements in topological affine planes. In 1940 Santaló showed [8], by an example, that Vincensini’s proof [9] of an extension of Helly’s theo...

Let G be a graph embedded in the plane and let A be an arrangement of pseudolines intersecting the drawing of G. An aligned drawing of G and A is a planar polyline drawing Γ of G with an arrangement A of lines so that Γ and A are homeomorphic to G and A. We show that if A is stretchable and every edge e either entirely lies on a pseudoline or intersects at most one pseudoline, then G and A have...