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14 votes
1 answer
783 views

What was Smith's proof of Smith's theorem on Hamilton cycles in cubic graphs?

In a short 1946 paper "On Hamiltonian Circuits", Tutte proved the famous result that an edge in a cubic graph lies in an even number of Hamilton circuits. He attributed the result to his friend CAB ...
Gordon Royle's user avatar
  • 12.7k
12 votes
1 answer
424 views

Quantitatively characterizing the failure of the converse of Dirac's theorem

First, I am an undergraduate so I apologize if this is trivial and certainly understand if it is closed immediately. I am currently in a combinatorics and graph theory class and recently we have ...
1729's user avatar
  • 221
9 votes
2 answers
2k views

"Gray code" of all permutations

Informally asking, can we step through all permutations of the set $\{1,\ldots,n\}$ by just using transpositions? More formally: For any $n\in\mathbb{N}$ let $[n] = \{1,\ldots,n\}$ and let $S_n$ be ...
Dominic van der Zypen's user avatar
9 votes
1 answer
399 views

Are bipartite Moore graphs Hamiltonian?

This is motivated by a computer-generated conjecture that bipartite distance-regular graphs are hamiltonian. I decided to check the case of Moore graphs first. The cycles and complete bipartite graphs ...
LeechLattice's user avatar
  • 9,501
7 votes
1 answer
210 views

Grinberg's uniquely hamiltonian 3-connected graphs (Russian paper)

Many years ago, Grinberg found some uniquely-hamiltonian $3$-connected graphs, and published his results in a paper that has been cited several times as follows. E. Grinberg, Three-connected graphs ...
Gordon Royle's user avatar
  • 12.7k
4 votes
0 answers
230 views

Is this case of Barnette's Conjecture known?

Context: Barnette's Conjecture is that every bipartite cubic polyhedral graph is Hamiltonian. I have been interested by this problem for a long time, and I recently came up with a result. From my ...
Zach Hunter's user avatar
  • 3,499
4 votes
0 answers
99 views

Maximal non-hamiltonian graphs - spanned by a theta graph?

At the moment I am interested in maximal non-hamiltonian graphs, so that is a (simple, undirected) graph that does not itself have a hamilton cycle, but if you add an edge between any two distinct non-...
Gordon Royle's user avatar
  • 12.7k
3 votes
0 answers
107 views

Reference request: Bipartite symmetric graphs are hamiltonian

Does anyone know whether bipartite symmetric graphs are hamiltonian? I'm not sure whether anyone have proved it before, but a nonhamiltonian symmetric bipartite graph would lead to a counterexample to ...
LeechLattice's user avatar
  • 9,501
0 votes
0 answers
86 views

Uniqueness of compatible cycle decomposition for Eulerian trail

Fleischner mentions in his article Uniqueness of maximal dominating cycles in 3-regular graphs and of hamiltonian cycles in 4-regular graphs about the uniqueness of compatible cycle decomposition that ...
False Equivalence's user avatar