Interval Visibility Graphs

Requires a Wolfram Notebook System
Interact on desktop, mobile and cloud with the free Wolfram Player or other Wolfram Language products.
Consider a vertical stack of open intervals, such as ,
,
,
. Two intervals are said to have vertical visibility if a vertical line can be drawn between two intervals without intersecting some other interval.
Contributed by: Ed Pegg Jr (September 2015)
Open content licensed under CC BY-NC-SA
Snapshots
Details
Reference
[1] Y. Chang, J. P. Hutchinson, M. S. Jacobson, J. Lehel, D. B. West, "The Bar Visibility Number of a Graph," SIAM Journal on Discrete Mathematics, 18(3), 2004, pp. 462–471. http://www.math.illinois.edu/~dwest/pubs/visno.pdf.
[2] M. Axenovich, A. Beveridge, J. P. Hutchinson, and D. B. West, "Visibility Number of Directed Graphs," SIAM Journal on Discrete Mathematics, 27(3), 2013 pp. 1429–1449. www.math.kit.edu/iag6/~axenovich/media/visibility.pdf.
Permanent Citation
"Interval Visibility Graphs"
http://demonstrations.wolfram.com/IntervalVisibilityGraphs/
Wolfram Demonstrations Project
Published: September 29 2015