TOPICS
Search

Crossed Prism Graph


CrossedPrismGraph

The term "n-crossed prism graph" is used in this work for the graph obtained from two disjoint cycle graphs C_n (for even n>=4), with vertices v_1, ..., v_n and v_(n+1), ..., v_(2n) in cyclic order, by adding edges (v_k,v_(n+k+1)) and (v_(k+1),v_(n+k)) for k=1, 3, ..., n-1.

The crossed prism graphs are cubic vertex-transitive (and hence appear in Read and Wilson 1998, though without any designation indicating membership in a special graph family), weakly regular, Hamiltonian, and Hamilton-laceable. The 2n-crossed prism graphs are toroidal for n>2 (E. Weisstein, May 9, 2023).

Simmons (2014) used the term "polygonal bigraph on 4m vertices" for graphs isomorphic to the m-crossed prism graph and investigated the Hamilton-laceability and structure of Hamiltonian paths in these graphs.

The cases n=4 and 6 have graph crossing number 0 and 2, respectively. For every even n>=4, drawing the two cycles as concentric circles and routing each pair of crossed joining edges within a separate sector of the annulus gives exactly n/2 crossings, proving the upper bound n/2. The upper bound is known to be attained for every even n with 8<=n<=26 and is conjectured to be attained for all even n>=8.

The first few crossed prism graphs and some of their properties are implemented in the Wolfram Language as GraphData[{"CrossedPrism", n}].

The n-crossed prism graph has independence polynomial

 I_n(x)=2^(-n)[(1+2x(2+x)-sqrt((1+2x)(1+6x)))^n+(1+2x(2+x)+sqrt((1+2x)(1+6x)))^n],

which has recurrence equation

 I_n(x)=(2x^2+4x+1)I_(n-1)(x)-x^2(x^2+4x+2)I_(n-2)(x).
TruncatedSquareLatticeGraph2x2

The n-crossed prism graph is isomorphic to the Haar graph H(2^(n+1)+2^(n/2)+1) and to the (1,2n,n-1)-honeycomb toroidal graph. The 8-crossed prism graph is isomorphic to the 2×2 truncated square lattice graph, illustrated above. Other special cases are summarized in the following table.


See also

Crossed Graph, Cubic Vertex-Transitive Graph, Cubical Graph, Cycle Graph, Franklin Graph, Helm Graph, Honeycomb Toroidal Graph, Ladder Graph, Möbius Ladder, Prism Graph, Truncated Square Lattice Graph, Web Graph

Explore with Wolfram|Alpha

References

House of Graphs. Crossed Prism Graphs. Cubic Vertex-transitive graph, 10-crossed prism graph, 12-crossed prism graph, 14-crossed prism graph, 16-crossed prism graph, 18-crossed prism graph, 20-crossed prism graph, 22-crossed prism graph, 24-crossed prism graph, Cube Q3, and Franklin Graph.Read, R. C. and Wilson, R. J. "Cubic Polyhedral Graphs: 8-16 Vertices." In An Atlas of Graphs. Oxford, England: Oxford University Press, pp. 159-163, 1998.Simmons, G. J. "A Surprising Regularity in the Number of Hamilton Paths in Polygonal Bigraphs." Ars Combin. 115, 335-341, 2014.

Referenced on Wolfram|Alpha

Crossed Prism Graph

Cite this as:

Weisstein, Eric W. "Crossed Prism Graph." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/CrossedPrismGraph.html

Subject classifications