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12 votes
0 answers
349 views

Matroids with prescribed independent sets

Let $A$ be a finite set. Let $B$ be a family of subsets of $A$. We are interested in a matroid with a minimum rank such that every element of $B$ is independent. The answer is obvious - a uniform ...
ilyaraz's user avatar
  • 1,791
5 votes
3 answers
461 views

Minimize distance between centroids of subsets of points

In a n-dimensional space, I want to divide a set of m points into v (non-empty) subsets. I want to minimize the sum of the pairwise Euclidean distances between the centroids of the resulting subsets. ...
Jen's user avatar
  • 51
5 votes
0 answers
581 views

When is polytope compatible with network flow?

A linear program is the problem of optimizing an linear objective function within some polytope $A$ over $\mathbf R^n$. My question is motivated by the question of when a linear programming problem ...
David Harris's user avatar
  • 3,475
2 votes
2 answers
330 views

Polynomial time algorithm for rigid graph isomorphism

We found, implemented and tested algorithm for graph isomorphism and it appears to be polynomial time if the graph is rigid. Q1 Is the algorithm below correct and polynomial time for rigid graphs? A ...
joro's user avatar
  • 25.4k
2 votes
0 answers
288 views

3-uniform hypergraphs and their circuit space

So, I'll break this post into two questions. Both concern 3-uniform hypergraphs. A 3-uniform hypergraph $H=(V,E)$ consists of a set of vertices $V$ and a set of edges $E$, where each edge $e\in E$ is ...
anthony mann's user avatar