THE ELECTRONIC JOURNAL OF COMBINATORICS (ed. June 2005), NOT OFFICIAL.

Venn Diagram Survey
Frequently Asked Questions

Because of the well-known nature of Venn diagrams there are many questions that people may have about them that are not answered by the survey. Some of these questions are gathered here, and some answers provided.

• Can I use the figures in the survey in my paper, web page, program, T-shirt, etc.?
  

  ANSWER: Generally, we will grant permission for non-commercial usage of the diagrams. However, the diagram renderings found on this website are copyrighted, so permission must be obtained in advance by writing to the first author and, when used, proper attribution must be given.

• Does there exist a Venn diagram on 4 curves?
  

  ANSWER: Yes, and on all higher number of curves. See the page What is a Venn Diagram?.

• What is the name for the area of intersection of two circles, such as in the standard drawing of a 2-Venn diagram?
  

  ANSWER: There does not appear to be a mathematical term for the area of intersection in general - please send us email if you know one.

  There is a symbol from Christian mysticism for the intersecting region of two circles as in the 2-Venn diagram; the name is `Viscera Pisces' and the region represents the intersection of the spheres of heaven and earth. The name (also spelled `vesica piscis') literally means "fish bladder" or "flesh of the fish" - if the edges of the intersecting region are extended beyond the ovoid shape, the lines form the early Christian fish symbol (as in this figure). The ovoid centre of the region is referred to as the `mandorla' (Latin for "almond").

• Is there any software available that will allow me to draw Venn diagrams, particularly where the area of the regions is proportional to the number of elements represented by that region and/or there is no restriction on the number of sets?
  

  ANSWER: This is a popular request; there are many answers.

  • There is a company called Stata Corporation which markets a software package, Stata, for statistical analysis. Stata has a module venndiag for drawing Venn diagrams, but I have no experience with it.
  • IBM has software GDDM which has some capability of drawing Venn diagrams, but I have no experience with it.
  • There are some educational programs that draw 3 and 2-Venn diagrams; for example this MSDOS program by John Masterson and David Lovelock of the University of Arizona.
  • As part of a graph drawing course Jacques Eloff developed some software for drawing non-planar "Venn diagrams". See this graph drawing page. They (w. Lynette van Zijl) also have a technical report about another aspect of drawing Venn diagrams.
  • Stirling Chow has developed applets called DrawVenn and DrawEuler for drawing area-proportional Venn and Euler diagrams in various forms. See the pages for DrawEuler and DrawVenn.

THE ELECTRONIC JOURNAL OF COMBINATORICS (ed. June 2005), NOT OFFICIAL.