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12 votes
4 answers
2k views

Cyclic Permutations - but not what you think

This question is not about elements of $S_n$ that consist of a single $n$-cycle, though naturally it's related. Instead, consider permutations modulo the action of $(123\ldots n)$. That is, we ...
kcrisman's user avatar
  • 367
10 votes
1 answer
269 views

Edge-transitive Cayley graphs of $S_n$

I came across the following question which I haven't seen before: Question. Fix $k\ge 3$. For infinitely many $n$, does there exists a generating set $\langle R_n \rangle = S_n$, $|R_n|=k$, such ...
Igor Pak's user avatar
  • 17k
9 votes
1 answer
356 views

Diameter of the modified bubble-sort graph

The modified bubble-sort graph is the Cayley graph $Cay(S_n,S)$ of $S_n$ generated by $n$ cyclically adjacent transpositions. Thus $S = \{ (1,2),(2,3),\ldots,(n,1)\}$. I was wondering whether the ...
Ashwin Ganesan's user avatar
7 votes
2 answers
421 views

3-coloring the alternating group graph

Consider the alternating group graph, here defined as a Cayley graph on the alternating group $A_n$ using the generating set $\{(1,2,3),(1,2,4),\dotsc,(1,2,n),(1,n,2),\dotsc,(1,4,2),(1,3,2)\}$. Note ...
vidyarthi's user avatar
  • 2,089
6 votes
3 answers
434 views

Repository of graph classes that are tough to test non-isomorphic pairs from isomorphic pairs

(1) Which graph classes are extremely tough to test for graph non-isomorphic pairs from isomorphic pairs? (2) Is there a repository of adjacencies from such classes?
Turbo's user avatar
  • 13.9k
4 votes
2 answers
485 views

Transposition Cayley graphs are planar

Consider the Cayley graph $G$ with vertex set the elements of the symmetric group $S_n$ and generating set the set of minimal transposition generators of the group $S_n$, that is the set $S=\{(12),(13)...
vidyarthi's user avatar
  • 2,089
3 votes
1 answer
149 views

Drunken X-mas polynomials for graphs

Given a finite connected graph $\Gamma$ with vertices $\lbrace 1,\ldots,N\rbrace$, we can consider the polynomial $$\sum_{\pi\in\mathcal S_N}x^{\sum_{j=1}^Nd_\Gamma(j,\pi(j))}$$ where $\mathcal S_N$ ...
Roland Bacher's user avatar
3 votes
0 answers
56 views

Groups that can occur as graph automorphisms of a fixed size graph

From theorem $4$ and corollary $1$ in this book we have that graph isomorphism has to do with automorphism group of a graph. We also know every group is the automorphism group of a graph by Frucht's ...
Turbo's user avatar
  • 13.9k
3 votes
0 answers
164 views

Generating sets of the symmetric group that yield isomorphic Cayley graphs

Let $S$ and $S'$ be subsets of size $k$ of $\mathfrak{S}_n$. Are there any necessary or sufficient conditions to determine whether or not $S$ and $S'$ yield isomorphic Cayley graphs? Assuming we ...
Anthony Labarre's user avatar