Questions on the use of Mathematica in combinatorics, including the Combinatorica add-on package.
5
votes
2answers
198 views
Sierpinski carpet with GraphData
Is this graph in the list among the so-called "standard" structures used in GraphData? However, I have not found, yet, anything like "Carpet" or "Sponge" in the ...
-1
votes
1answer
42 views
Permutation of arguments of product of functions
Given a function, g, which is symmetric in its argument, g(a,b)=g(b,a), consider the product g(a,b)*g(c,d)*g(e,f). I would like to get all the permutations of this product with respect to the ...
0
votes
0answers
31 views
Identify columns of a huge matrix just polynomially many rows chosen at random
I am interested in the following problem in combinatorics $\Cap$ Probability. Let $\lambda \in \mathbb{N}$ be a parameter. Consider a matrix of $2^\lambda$ rows and $2^\lambda$ columns. Each column ...
4
votes
4answers
232 views
Listing matrices up to symmetry
I am interested in the equivalence relation on N x N binary matrices, in which two matrices are equivalent if one can be obtained by rotating/reflecting the other. I would like to obtain a list
...
0
votes
0answers
92 views
My algorithm produces too many permutations
Imagine the following problem. A population of size $n$ consists of $i$ men and $n-i$ women. The population goes to the casino. Call $g_m$ ,$g_w$ the amount of money won by men and women respectively. ...
0
votes
0answers
66 views
Get path to end nodes in directed (partially cyclic) graph
I have a large directed graph containing small loops. I would like to extract all paths to all end nodes (no VertexOutComponent) with a given path length $n$. I ...
4
votes
0answers
62 views
Generating ALL spanning trees in an undirected graph
I was wondering if there is explicit source code for generating all spanning
Trees on undirected Graphs. I don’t need anything very
fancy – perhaps Minty's algorithm or Gabow&Myers. I've only ...
1
vote
0answers
97 views
Shapley value and Mathematica [closed]
I use the TuGames package in Mathematica to analyze
cooperative games. Is it possible to calculate Shapley
value, Nucleolus, etc., for a large number of players like
400 or more?
5
votes
0answers
80 views
Is there a function to generate a minimal clique cover?
This is a graph problem known as the "Clique Edge Cover" or "Intersection Number" problem, and the goal is to find, from a given graph like $E=\{\{a,b\},\{a,c\},\{b,c\},\{b,d\},\{c,d\}\}$ and ...
2
votes
1answer
76 views
PermuteSubgraph not working? (Combinatorica)
I am trying to write a code to perform the QAP partialling analysis (here's a paper to know more) but the part in which I "scramble" the graph with PermuteSubgraph does nothing, I am actually not ...
0
votes
0answers
36 views
Generating partitions of a set with a specified size of the parts [duplicate]
I tried the following (inspired by the answer here)
myList = {a, b, c};
Needs["Combinatorica`"];
SetPartitions[myList]
and I got this answer,
...
2
votes
1answer
71 views
How to enumerate multisets
Given the eight-element set {1,2,3,4,5,6,7,8}, I would like to enumerate all multisets (subsets with repetition) of size n, where n >=3. For example, with n = 3, the sets {1,1,1}, {1,1,2}, ..., ...
0
votes
0answers
47 views
Generating partitions of a set [duplicate]
Is it possible to get Mathematica to generate all possible partitions of a set of objects?
(..or equivalently if it can be made to do the cumulant expansion or at least the Gaussian special case of ...
10
votes
1answer
106 views
How do I expand StirlingS2[n, 10] in terms of elementary functions?
I know that it is possible to expand StirlingS2[n, 10] in terms of elementary functions of n. I tried ...
4
votes
1answer
130 views
Combinations which do not have elements in common
I can choose 2 letters from the four letters $\{A,B,C,D\}$ in 6 combinations using the combination formula
$$\frac{n!}{ r! (n-r)!}$$
...
