THE ELECTRONIC JOURNAL OF COMBINATORICS (ed. March 2001), DS #5.

An Irreducible Venn Diagram


This is an irreducible diagram derived from the ellipse diagram on the main page. Removing curve 4 results in an independent family in which the region corresponding to the set {1} is disconnected (the cyan shaded region of the figure above). Since the diagram is symmetric, no matter what curve is removed, the result is not a Venn diagram.
THE ELECTRONIC JOURNAL OF COMBINATORICS (ed. March 2001), DS #5.