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Let G be an undirected graph having the vertices V={1,...,n}. A subset {i,j,k} is said to be a triangle of G if the complete graph with these vertices is a subgraph of G.
How to find the number of all triangles of G in an optimal way? The code should work with RandomGraph(400,1000).

Using the tree structure example from ?GraphTheory[DrawGraph] using showlabels=true the highlighted areas are merged and no amount of zooming can seperate the merged yellow areas.

Another issue, I don't see the advantage of style=tree when a tree structure can only be printed if the original DrawGraph is already represented as a tree style structure when...

A list of small graphs with associated pictures and tables of
values of various graph invariants.

The graph invariants were made using Maple programs which uses
the networks and GraphTheory packages.

A picture presents some inequality conjectures between the graph invariants.

http://www.msci.memphis.edu/~speeds/

Sam Speed   August 29, 2011

Hi! I have been searching the forum, but with no luck.  How do I get maple to handle graphs with multiple edges between vertices?  I can't seem to find a function for this.  Does one exist?  I tried to do this by coloring the edges, but they just get re-colored.

EE1:=[1, 2], [3, 1], [2, 3], [4, 5], [6, 4], [5, 6], [7, 8], [9, 7], [8, 9];
EE2:=[2, 3], [4, 2], [3, 4], [5, 6], [7, 5], [6, 7], [1, 8], [9, 1], [8, 9];
EE3:=[3, 4], [5, 3], [4, 5], [6, 7...

The AddVertex command (in GraphTheory) does not seem to copy any attributes that were set in the original graph.

with(GraphTheory):
G := CompleteGraph(5):
SetGraphAttribute(G,"graphAtt" = 1);
SetVertexAttribute(G,1,"vertexAtt" = 1);
SetEdgeAttribute(G,{1,2},"edgeAtt" = 1);
H := AddVertex(G,6):
GetGraphAttribute(H,"graphAtt");
                     ...

Does anyone know how to control the placement of the directional arrows for a digraph?

Here's an example:

with(GraphTheory):

G := Digraph(Trail(4,2,1,3,4,5),Trail(6,8,9,7,6,5));

SetVertexPositions(G,[[0,1],[1,1],[0,0],[1,0],[2,0],[3,0],[4,0],[3,1],[4,1]]);

DrawGraph(G);

produces:

The...

Can anyone help me understand why the following happens?

N := GraphTheory[Digraph]({[1,3],[3,9],[9,27]});

GraphTheory[IsNetwork](N);

and

M := GraphTheory[Digraph]({[1,2],[2,4],[4,8]}); 

GraphTheory[IsNetwork](M);

both indicate that the graph is not a network.  On the other hand, for numbers n other than 2 and 3, Maple does recognize the graph {[1,n],[n,n^2],[n^2,n^3]} as a network.

This procedure that I wrote:

Hey,

I've been running the following program in a maple worksheet and it has worked fine.

Now I want to run it on an Ubuntu machine that has some extra computing power to get through a big data set.

However I get strange "Incomplete Quoted Name" errors, even when I have no quoted names in my input at all.

This is just alittle bit of the output I'm getting:

    |\^/|     Maple 14 (X86 64 LINUX)
._|\|   |/|_. Copyright (c...

Hey everyone,

I've been using nonisomorphicgraphs for a while now, and my professor would really like to know if there is a pattern in the order in which it spits out the graphs. I've noticed that they pair them up in complements of each other(or as close as possible), but has anyone found the order in which they come out, and what the reason for this order is?