GV

GeezerVison

The World Wide Web, restored to 800 pixels of glory.

Home|About|Gaming cabinet|Archives|How it works|Starter sites

On this site

  • Algebra
  • Applied Mathematics
  • Calculus and Analysis
  • Discrete Mathematics
  • Foundations of Mathematics
  • Geometry
  • History and Terminology
  • Number Theory
  • Probability and Statistics
  • Recreational Mathematics
  • Topology
  • Alphabetical Index
  • Random Entry
  • New in MathWorld

This view

  • Original page
  • New address

GeezerVison is showing mathworld.wolfram.com — Graph Join -- from Wolfram MathWorld

Search

Graph Join


DOWNLOAD Mathematica NotebookDownload Wolfram Notebook
GraphJoin

The graph join G=G_1+G_2 of graphs G_1 and G_2 with disjoint sets V_1 and V_2 of vertices and edge sets X_1 and X_2 is the graph union G_1 union G_2 together with all the edges joining V_1 and V_2 (Harary 1994, p. 21). Graph joins are implemented in the Wolfram Language as GraphJoin[G1, G2].

In particular, if K_1 is the singleton graph, then the graph corona product K_1 circledot H is the graph join K_1+H.

A complete k-partite graph K_(i,j,...) is the graph join of empty graphs on i, j, ... nodes. A wheel graph is the join of a cycle graph and the singleton graph. Finally, a star graph is the join of an empty graph and the singleton graph (Skiena 1990, p. 132).

The following table gives examples of some graph joins. Here K^__n denotes an empty graph (i.e., the graph complement of the complete graph K_n), C_n a cycle graph, and K_1 the singleton graph.

productresult
K^__i+K^__j+...complete k-partite graph K_(i,j,...)
C_n+K_1wheel graph W_(n+1)
K^__n+K_1star graph S_(n+1)
C_n+K^__2n-dipyramidal graph
C_m+K^__ncone graph C_(m,n)
K^__m+P_nfan graph
mK_(n-1)+K_1windmill graph D_n^((m))

See also

Cone Graph, Dipyramidal Graph, Fan Graph, Graph Cartesian Product, Graph Sum, Graph Union, Simonovits Product Conjecture, Star Graph, Wheel Graph, Windmill Graph

Explore with Wolfram|Alpha

WolframAlpha

More things to try:

  • {{1,0,-1},{2,-1,3}} column space
  • Cantor's Paradox
  • Mandelbrot set

References

Harary, F. Graph Theory. Reading, MA: Addison-Wesley, pp. 21 and 167-168, 1994.Skiena, S. "Joins of Graphs." §4.1.3 in Implementing Discrete Mathematics: Combinatorics and Graph Theory with Mathematica. Reading, MA: Addison-Wesley, pp. 131-132, 1990.

Referenced on Wolfram|Alpha

Graph Join

Cite this as:

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

Subject classifications

You are visitor 01402503 — GeezerVison does not store the pages you look up.
Best viewed with Netscape Navigator 4.7 or Internet Explorer 6 at 800×600. No cookies required.