Stratified graphs for imbedding systems. Lower bounds for the average genus. Overlap matrices and total imbedding distributions. On the average genus of a graph. Kuratowski-type theorems for average genus.
Limit points for average genus.
2-connected nonsimplicial graphs. Limit points for average genus. Local extrema in genus-stratified graphs. Genus distributions for bouquets of circles. Genus distributions for two first classes of graphs.