Petersen Graphs
``The'' Petersen graph is the Graph illustrated above possessing ten Vertices all of whose nodes have Degree 3 (Saaty and Kainen 1986). The Petersen graph is the only smallest-girth graphwhich has no Tait coloring.
The seven graphs obtainable from the Complete Graph 
by repeated triangle-Y exchanges are also called Petersengraphs, where the three Edges forming the Triangle are replaced by three Edges and a new Vertex that form a Y, and the reverse operation is also permitted. AGraph is intrinsically linked Iff it contains one of the seven Petersen graphs(Robertson et al. 1993).
References
Adams, C. C. The Knot Book: An Elementary Introduction to the Mathematical Theory of Knots. New York: W. H. Freeman, pp. 221-222, 1994. Robertson, N.; Seymour, P. D.; and Thomas, R. ``Linkless Embeddings of Graphs in 3-Space.'' Bull. Amer. Math. Soc. 28, 84-89, 1993. Saaty, T. L. and Kainen, P. C. The Four-Color Problem: Assaults and Conquest. New York: Dover, p. 102, 1986.
- Determinant Expansion by Minors
- Determinant (Knot)
- Determinant Theorem
- Developable Surface
- Deviation
- Devil on Two Sticks
- Devil's Curve
- Devil's Staircase
- Diabolical Cube
- Diabolical Square
- Diabolo
- Diacaustic
- Diagonalization
- Diagonal Matrix
- Diagonal Metric
- Diagonal (Polygon)
- Diagonal (Polyhedron)
- Diagonal Ramsey Number
- Diagonal Slash
- Diagonal (Solidus)
- Diagonals Problem
- Diagram
- Diameter
- Diameter (General)
- Diameter (Graph)