THE ELECTRONIC JOURNAL OF COMBINATORICS 4 (1997), DS #5.

Venn Diagram Survey
Footnotes

Footnotes:

1 By C(n,k) we denote the binomial coefficient n!/(k!(n-k)!).

2 Two figures in the plane are congruent if one can be transformed into the other by rotations and translations in the plane.

3 A graph is three-connected if the removal of any two vertices (and the adjacent edges) leaves a connected graph.

4 The prism of a graph G is formed by taking two copies of G and adding a perfect matching whose edges join corresponding copies of vertices.

5 A planar graph is one that can be embedded in the plane without crossing edges. A plane graph is a planar graph that has been embedded in the plane.

6 The square of a graph G, denoted G2, is the graph obtained from G by adding edges between vertices if they are at distance 2 in G. All of the original edges of G are present in G2.

7 A link is a finite collection of knots. A Brunnian link is a link which is non-trivial, yet every proper sub-collection is trivial. A trivial link is one that can be projected to a collection of circles in the plane.

THE ELECTRONIC JOURNAL OF COMBINATORICS 4 (1997), DS #5.