Desargues graph

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This article defines a particular undirected graph, i.e., the definition here determines the graph uniquely up to graph isomorphism.
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Definition

The Desargues graph is a particular graph on 20 vertices defined in the following equivalent ways:

  1. It is the Levi graph of the Desargues configuration
  2. It is the bipartite Kneser graph with parameters 5,2
  3. It is the generalized Petersen graph G(10,3).

Arithmetic functions

Size measures

Function Value Explanation
size of vertex set 20 As Levi graph of Desargues configuration: number of points + number of lines in the configuration = 10+10=20
As bipartite Kneser graph with parameters n=5,k=2: 2(nk)=2(52)=2(10)=20
As generalized Petersen graph G(n,k),n=10,k=3: 2(10)=20
size of edge set 30 As Levi graph of Desargues configuration: number of incidences between points and lines = (number of lines) * (number of points on each line) = (10)(3)=30
As bipartite Kneser graph with parameters n=5,k=2: (nk,k,n2k)=n!k!k!(n2k)!=(52,2,1)=30
As generalized Petersen graph G(n,k),n=10,k=3: 3n=3(10)=30