Questions about handling graphs in Mathematica, graph theory, graph visualization, GraphPlot, the built-in Graph type and the Combinatorica` package.

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0answers
15 views

Independence Number of Graphs [on hold]

Suppose $\alpha(G)\leq\alpha(H)$ where $G$ and $H$ are graphs, and $\alpha(.)$ is the independence number of graph. Is the following statement true? $\alpha(G\boxtimes G) \leq \alpha(H\boxtimes H)$ ...
1
vote
0answers
36 views

Draw mesh edge / map a graph to a mesh

I am doing a "force density" method to generate a mesh under certain load. The original mesh is like this: Then, I generate a IncidenceMatrix from the graph for further matrix transformation and ...
-1
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0answers
28 views

Graph Theory Cut Vertex [on hold]

so I recently started learning about the graph theory and i came about this question: Show that a vertex c in the connected simple graph G is a cut vertex if and only if there are vertices u and ...
4
votes
1answer
405 views

Something interesting about Pi, but something seems amiss

I saw something interesting about text-analysis - bigrams - in Basic Text Analysis in Mathematica I wondered how the bigrams of Pi's digits might appear. As expected, take enough terms and every ...
1
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0answers
27 views

Successive addition or deletion of vertices (or edges) in graph

I am trying to perform a kind of dynamic graph simulation where vertices and edges of graph are added and deleted according to the current state of the graph at each time step. I know that there are ...
0
votes
2answers
96 views

Random geometrical graph generation

I would like to generate a random graph on $[0,1]^2$. Each node is connected to one other if the distance between two nodes is say 1/4 or less. Here is an example with 50 nodes and 200 edges I would ...
0
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0answers
37 views

Trying to write a program to find an approximate harmonic function on a given graph using relation method

So given an undirected graph with two vertices that have fixed values assigned to them, a harmonic function is a function that assigns values to all other vertices such that the value assigned to each ...
4
votes
1answer
131 views

VertexRenderingFunction (or EdgeRenderingFunction) with movable nodes?

In GraphPlot, I'd like to use VertexRenderingFunction (VRF) and have the resulting object behave the same way under dragging verticies as it does when I do not use VRF. The same issue occurs for ...
1
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0answers
44 views

What do the default shapes/colors in DiscreteMarkovProcess Graph mean?

In making markov chains, I know how to do that, but I am curious as to what the different colors, and shapes of the vertexes in the graph output mean. as example; ...
0
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1answer
44 views

EdgeRenderingFunction For 2 Vertices in a Loop

Assume there is a set of rules: set = {"A" -> "B", "B" -> "A", "B" -> "C", "C" -> "D", "D" -> "A", "C" -> "C"}; which we want to graph using ...
2
votes
2answers
47 views

Efficiently or Elegantly construct linear graph list from vertex pairs

I am processing MRP data, with BOM relations as pairs of part number strings. I want to construct lists that represent the linear graphs defined by these pairs. Here is some code to generate random ...
1
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0answers
18 views

FindIndependentEdgeSet behaves differently in v9 and v10

The following code gets different output in v9 and v10. ...
5
votes
2answers
159 views

Drawing a path which realises the diameter of the graph

So I enter a (0,1) adjacency matrix and I get the following graph: The diameter of this graph is 4. How can I ask that two vertices which realise this diameter be drawn with different filling ...
7
votes
2answers
266 views

Is there a bug in FindClique?

If h is a graph, FindClique[g, {n}] should return a clique on exactly $n$ vertices if one exists in ...
1
vote
1answer
23 views

Adding a title to TreePlot

This is a basic question I am sure, but cannot seem to find the answer in the documentation. Does anyone know how to add a title to a TreePlot?
2
votes
2answers
43 views

Color edges of a multigraph when there are parallel edges using Graph[] and EdgeStyle

This a related question to : How can I display a multigraph with different colored edges? However I'm not using GraphPlot. Instead I'm using Graph and EdgeStyle attribute. Take this graph : How can ...
6
votes
4answers
183 views

Automatically convert pairs of directed edges to an undirected edge?

I have a directed graph, which for some pairs of vertices, has a directed edge between them in each direction. I would like to replace such pairs of directed edges between the same vertices but in ...
0
votes
0answers
33 views

Error with AppendTo [duplicate]

I am trying to write a function that builds a graph, or - better said - adds a layer of leaves to a pre-existing graph. Basically, I hand to the function three lists. ...
0
votes
0answers
43 views

Draw a single disconnected vertex [duplicate]

I am just started using Mathematica. I am trying to split my graph into two sets. 1. How does Mathematica split the graph into 2 subgraphs (connected or disconnected)? 2. How can I draw a graph with ...
1
vote
1answer
69 views

LayeredGraphPlot: how to specify edge endpoints?

What directive within the LayeredGraphPlot command specifies where the edges attach to vertices? For example, instead of the left output below, I'd like to have the right one. ...
2
votes
1answer
41 views

`TransitiveClosureGraph` doesn't return self-loops for nodes that are in a cycle

This is from boost library documentation: The transitive closure of a graph G = (V,E) is a graph G* = (V,E*) such that E* contains an edge (u,v) if and only if G contains a path (of at least ...
3
votes
2answers
112 views

Using GraphData to generate all directed graphs with n vertices

Using Combinatorica, it was possible to generate unlabeled (non-isomorphic) directed graphs of |V|=n. Here the example is for n=4 ...
0
votes
1answer
38 views

Export and Import a list of graphs?

I want to export a list of graphs that come as output to my program. However, I tried exporting all the graphs as graphs using Map and an Export statement with "graph.gml" statement, but got an error. ...
1
vote
1answer
43 views

Is there a way to combine VertexLabeling->True and VertexLabels/Tooltip in TreePlot?

Basically, I'm trying to make Mathematica give me a tree with names inside the rectangles like so: ...while also having the properties of VertexLabels or Tooltip, which lets me place my mouse over ...
5
votes
4answers
97 views

Vertex styling in CommunityGraphPlot

Is there a way to change the colours of nodes within one community? Mathematica assigns vertex colours automatically to each community. However, I'd rather like to use my own colour set. ...
2
votes
1answer
223 views

LayeredGraphPlot Vertex Spacing / Edge Length

For anyone who has used LayeredGraphPlot (Mma v9), you have probably seen that the vertex spacing is consistent throughout, that vertices have the same minimum unit ...
0
votes
1answer
37 views

How to query W|A, to get a list of asymmetric, bicubic and $3$-edge colorable graphs? [closed]

I'm interested in finding graphs with certain properties, like the smallest cubic bipartite asymmetric graph. While working on a related graph-theoretic problem, concerning edge-colrings, I came along ...
1
vote
2answers
62 views

Insert an element to AdjacencyGraph

I'm not able to insert an element to mine AdjacencyGraph. I suppose that i should modify my AdjcencyMatrix: ...
1
vote
0answers
39 views

Purpose of VertexWeight

I am trying to partition a graph into partitions of equal weight (on the vertex). I looked at the documentation, and found VertexWeight, which seems to attach a weight to a vertex. In the details, ...
0
votes
0answers
66 views

How to recursively check is a graph is a binary search tree?

I'm having trouble using the built in DepthFirstScan[] to see if a tree satisfies the binary search tree property, the documentation is confusing. Motivation: I'm ...
1
vote
0answers
45 views

Multi-named Nodes (or Overlapping Nodes) in TreePlot, or Merging Trees

If there is a series of rules from which a TreePlot is made: {D->C, C->B, B->A} And a new node is added that is technically the same as an existing ...
4
votes
3answers
195 views

Graph Coloring based on neighboring vertices? Cellular Automata

I would like to apply a majority rule cellular automata to graphs. Specifically, I would like to take a graph as input, and then define two functions, InitialColoring[graph] and MajorityRule[graph]. ...
9
votes
3answers
252 views

Label multiple edges between same vertices

I have a simple graph with multiple edges between two vertices, say: Graph[{ Labeled[a -> b, "A"], Labeled[a -> b, "B"] }] Unfortunately, Mathematica ...
0
votes
0answers
43 views

Independent Set Sorting

Let's say I have a graph g, and I wanted the largest independent vertex set of g. I would write then, ...
3
votes
1answer
52 views

Change group generators?

I want to make Cayley graphs for the same group, but with different generators. Is there any way to represent a group, besides a cumbersome permutation representation or using the default Mathematica ...
3
votes
1answer
58 views

AdjacencyMatrix: Unexpected output

I have a graph defined as follow: ...
1
vote
1answer
184 views

How to implement the directed Barabasi-Albert algorithm in Mathematica?

Does anyone know how to implement an efficient version of the [directed Barabasi-Albert algorithm][1] in Mathematica that scales until hundred of thousands nodes? The directed network mechanism is ...
1
vote
1answer
63 views

How to insert Tooltip into incidence plot?

I'm trying to make a graph using a file .NET extracted from a file .CSV and to make tooltiped the vertices' labels. Initially I ...
1
vote
1answer
75 views

Distinguishing left from right adjacent triangles in triangle mesh

What I'm trying to do: I'm trying to create a path-drawing function which will produce a path like the one I-P in the diagram below. The way this path was generated requires me to swap between the ...
2
votes
1answer
43 views

AdjacencyList of DirectedEdges in Graph ignore edge direction

I have a simple tree graph with directed edges: In: AdjacencyList[Graph[{a -> b, a -> c, b -> d, b -> e}], b] Out: {a, d, e} I wonder how I can ...
2
votes
1answer
56 views

Specifying the style of edges in directed graphs [closed]

How do I specify the style of individual edges in a directed graph (in Mathematica version 9)? Consider maybe this ...
3
votes
2answers
62 views

IsomorphicGraphQ giving an error when the graphs contain multi-edges

If I run IsomorphicGraphQ on the following graphs, I get an error I don't understand: ...
0
votes
0answers
50 views

Is it possible to use EdgeCapacity in FindMinimumCostFlow?

I'm having trouble getting the EdgeCapacity feature in FindMinimumCostFlow to work. I have attached a simple example. We have a simple graph of four vertices. There are two paths from the "source" ...
4
votes
2answers
97 views

Using VertexDelete to remove vertices by degree

I am trying to remove vertices that have degree less than 2, but I think I am missing something basic. I was hoping that I could use: ...
1
vote
0answers
29 views

Export format for graphs loses type information?

I have a situation where I am adding properties to vertices in my graph. In my case, I am adding a moduleId, which is an integer, and a kind, which is a string. I attach a weight to the edge as well. ...
0
votes
1answer
46 views

FindCycle not working as expected for multigraph

Say I have a simple multigraph like so: edges = {DirectedEdge[a, b], DirectedEdge[b, c], DirectedEdge[c, a]}; g = Graph[Join[edges, edges]] ...
2
votes
0answers
43 views

Bugs in VertexContract function?

I think there may be two bugs in the VertexContract function: 1) The updated graph does not include reasonable edgeweights 2) The function does not actually reduce the number of vertices in the ...
2
votes
1answer
59 views

Finding if a graph contains an even cycle

I am looking for a simple boolean-like function which could check if a graph contains an even cycle. I'm aware there is ExtractCycles but I'm looking for a true/false output than a list of cycles.
4
votes
1answer
203 views

Is it possible to draw a curved edge between two vertexes of a graph? [duplicate]

The following code generates a graph. ...
2
votes
1answer
96 views

Intelligent vertex placement in large tree graphs

This question about graph layout is fairly general, but can be illustrated in the case of the Collatz Conjecture. Collatz created the following function over integers greater than 1: If the integer ...