0
votes
0answers
69 views
Notation for substructure, especially for permutations?
Is there a standard notation that expresses substructure?
The specific case that I care about is the following:
Suppose $\sigma,\tau$ are permutations such that $$\sigma(x)\not=x\ …
0
votes
2answers
129 views
Ihara zeta function (graph theory) coefficients using a line graph
I'VE COMPLETELY REVISED MY QUESTION
I wish to take a simple undirected graph (i.e. the complete graph K_4)
Arbitrarily direct said graph, and then create a line graph from the d …
6
votes
3answers
557 views
2-cycle of K3 surface
Hi there,
I want to ask about the 2-cycle of K3 surface.
As we know, its betti number $b_2$=22, so there will be 22 2-cycle generators.
Is there any topological way to figure ou …
4
votes
0answers
109 views
Reciprocity Map and Cycle Class Map
This might be a very naive question but here it goes. Let X be a smooth variety of dimension d over a p-adic field. We have the n part of the rerciprocity map:
$rec/n: SK_1(X)/n \ …
4
votes
0answers
129 views
Expected number of components with multiple cycles in a subgraph of a square lattice
Short version
Is there an understanding of the emergence and subsequent disappearance of components with zero, one, or more cycles in a random subgraph of a square or cubic lattic …
0
votes
2answers
720 views
How many edge-disjoint cycles of length 3 are in the complete graph?
A couple of questions related to edge-disjoint cycles.
Let $K_n = (V,E)$ be the complete graph on $|V|=n$ nodes. Two cycles are 'edge disjoint' if they do not share any edges.
…
0
votes
1answer
140 views
finding missing edge in DAG which, when added, would create the longest cycle
Hey all,
Not sure if this is a math problem or an algorithm problem - but hoping it has a math style answer.
If I have a directed graph I can find all the closed loops - easy. ( …
1
vote
1answer
173 views
Need input on a potentially NP-hard maximal edge-weighted multi-cycle graph
I've posted a question on Stack Overflow regarding a seemingly NP-hard problem on maximization of weighted cycles in a graph problem.
One of the respondents cited Professor David …
1
vote
1answer
177 views
Definition of convex cycles
Consider the following definition.
Let $C$ be a cycle of a simple graph $G$. We say that $C$ is convex if for any pair of distinct vertices $u,v \in V(C)$ $$ d_C(u,v) < d_{G-C} …
0
votes
3answers
2k views
Cycle of length 4 in an undirected graph
Can anyone give me a hint for an algorithm to find a simple cycle of length 4 (4 edges and 4 vertices that is) in an undirected graph, given as an adjacency list? It needs to use $ …
4
votes
2answers
396 views
Ramification divisor associated to a cover of a regular scheme
Let $S$ be the spectrum of $\mathbf{Z}$ or the spectrum of an algebraically closed field. (Actually, one can take $S$ to be any noetherian integral regular scheme.)
Let $f:X\longr …
-2
votes
0answers
328 views
Showing that a graph has a cycle length less than something [closed]
Hi guys,
I have the following exercise to do but don't know how to approach it:
Let G be a graph with n nodes (n ≥ 2), and where every node has degree at least 3. Show that G has …
2
votes
1answer
409 views
Compute number vertex disjoint cycles in graph surrounding a face
Hi all,
If anyone has insight into the following variant of the classic problem of packing vertex-disjoint cycle into graphs I would be interested.
Given a finite undirected g …

