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# Bull Graph

The bull graph is a simple graph on 5 nodes and 5 edges whose name derives from its resemblance to a schematic illustration of a bull or ram (whose face is the triangle and horns are the graph's two bridges). It could perhaps equally well be called the "for all-graph" or "A-graph," and unfortunately sometimes is (e.g., Farrugia 1999, p. 2), even though that term is usually applied to a particular 6-node graph.

The bull graph is implemented in the Wolfram Language as GraphData["BullGraph"].

The bull graph is also chromatically equivalent to two distinct graphs illustrated above, all of which share the chromatic polynomial .

## See also

A Graph, Chromatically Unique Graph, Longhorn Graph

## Explore with Wolfram|Alpha

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## References

Brandstädt, A.; Le, V. B.; and Spinrad, J. P. Graph Classes: A Survey. Philadelphia, PA: SIAM, p. 18, 1987.Farrugia, A. "Self-Complementary Graphs and Generalisations: a Comprehensive Reference Manual." Aug. 1999. http://www.alastairfarrugia.net/sc-graph/sc-graph-survey.pdf.ISGCI: Information System on Graph Class Inclusions v2.0. "List of Small Graphs." http://www.graphclasses.org/smallgraphs.html.West, D. B. Introduction to Graph Theory, 2nd ed. Englewood Cliffs, NJ: Prentice-Hall, p. 12, 2000.

## Cite this as:

Weisstein, Eric W. "Bull Graph." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/BullGraph.html