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1 answer
438 views

Categories associated to digraphs

Let's take a directed graph, or a digraph, $G=(V,E)$ given by a finite set of vertices $V$ and a finite set of edges $E$. We can assume that pairs of vertices can have parallel edges between them and ...
Henri Riihimäki's user avatar
3 votes
0 answers
144 views

Counting homologically non-trivial and trivial cycles in $n \times n$ square lattice torus of a given length $l \geq n$

This should be a fairly standard question but I can't really seem to find a reference. Consider an $n \times n$ square lattice torus $\mathbb T$. Given a length $l \geq n$, what is the number of ...
Sanchayan Dutta's user avatar
21 votes
7 answers
1k views

Reference for topological graph theory (research / problem-oriented)

I would be interested in recommendations for topological graph theory texts. I think Gross and Yellen has a great chapter on topological graph theory, and I find Mohar and Thomassen's Graphs on ...
7 votes
0 answers
281 views

Relations between Betti numbers for clique complex

Given a clique complex $K$ constructed from a discrete set of vertices (i.e. its faces are isomorphic to the set of cliques in the 1-skeleton of $K$.), it seems that the Betti numbers $\beta_k$ ...
Henry.L's user avatar
  • 8,071
7 votes
1 answer
393 views

Kneser graph with overlap

Consider a graph with the vertices being all subsets of size $n$ of a set of size $2n$. Two vertices are connected if their overlap has size at most one. What is the chromatic number of this graph? ...
pi66's user avatar
  • 1,209