- chordal_cycle_graph(p, create_using=None)¶
Returns the chordal cycle graph on
The returned graph is a cycle graph on
pnodes with chords joining each vertex
xto its inverse modulo
p. This graph is a (mildly explicit) 3-regular expander .
pmust be a prime number.
- pa prime number
The number of vertices in the graph. This also indicates where the chordal edges in the cycle will be created.
- create_usingNetworkX graph constructor, optional (default=nx.Graph)
Graph type to create. If graph instance, then cleared before populated.
The constructed undirected multigraph.
create_usingindicates directed or not a multigraph.
Theorem 4.4.2 in A. Lubotzky. “Discrete groups, expanding graphs and invariant measures”, volume 125 of Progress in Mathematics. Birkhäuser Verlag, Basel, 1994.