Questions tagged [regular-graph]
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6 questions with no upvoted or accepted answers
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How to construct 4-regular graphs with few Hamiltonian decompositions?
A Hamiltonian decomposition of a finite simple graph is a partition of its edge set so that each partition class forms a Hamiltonian cycle. This is only possible if the graph is $2k$-regular.
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If the girth of a $2k$-regular graph $G$ is larger than the diameter of a tree $T$ with $k$ edges, then $G$ is decomposed into copies of $T$
I want to prove that ‘If the girth of a $2k$-regular graph $G$ is larger than the diameter of a $k$-edge tree $T$, then $G$ is covered by edge-disjoint copies of $T$.’
I tried several ways to solve ...
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Chromatic number of regular graphs using spectra
There exist inequalities relating the maximum and minimum eigenvalues of the adjacency matrix of a graph with its chromatic numbers, i.e. the Wilf's and Hoffmann's inequalities, which put together ...
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Random graphs constructed by many large matchings
Let $G_{n,d}$ be $d$-regular random graph. We know that for $d \geq 3$, $G \in G_{n,d}$ a.a.s. has a $1$-factorisation when $n$ is even.
So, the resulting graph that obtained from randomly choosing $d$...
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A question related to contiguity of random regular graphs
I am looking for a reference for the following fact. Let $r\geq 3$ be constant, let $G(n,r-2)$ be a random (simple) $(r-2)$-regular graph and let $H(n)$ be an independent random Hamiltonian cycle (on ...
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The diameter of random regular graphs
In 1982, B. Bollobas and Vega in the paper gave the configurational model to generate $r$-regular random graphs. They gave the following theorem (Theorem 1 in the paper).
Theorem: Let $r\geq 3$ and $\...