On 2-Embeddable Graphs
H. Schumacher · 1990
Let there be a graph without loops G and a closed surface F of the charac-teristic N.1) G is called embeddable in F if G can be represented (drawn) on F in such a way that none of G’s edges is crossing over another edge of G. In more general terms, G is called n-embeddable in F (n ∈ N), if G can be represented on F in such a way that each edge of G crosses a maximum of n other edges of G. On each edge of G, all intersections (points where edges are crossing) are counted; if one edge is crossed i times by another, this will be counted i times, if an edge is crossed by j multiple edges e1,e2,....,ej 2) this will be counted j times.