visibility graph
Obstacle number of planar graphs ★
Author(s): Alpert; Koch; Laison
Does there exist a planar graph with obstacle number greater than 1? Is there some such that every planar graph has obstacle number at most ?
Keywords: graph drawing; obstacle number; planar graph; visibility graph
Point sets with no empty pentagon ★
Author(s): Wood
Problem Classify the point sets with no empty pentagon.
Keywords: combinatorial geometry; visibility graph