
pair-crossing number
Are different notions of the crossing number the same? ★★★
Problem Does the following equality hold for every graph
?

![\[ \text{pair-cr}(G) = \text{cr}(G) \]](/files/tex/8cece1e00bb0e9fc122e0a5cad0dab2681cf33a4.png)
The crossing number of a graph
is the minimum number of edge crossings in any drawing of
in the plane. In the pairwise crossing number
, we minimize the number of pairs of edges that cross.
Keywords: crossing number; pair-crossing number
