## Abstract Let __h(n__) be the largest integer such that there exists a graph with __n__ vertices having exactly one Hamiltonian circuit and exactly __h(n__) edges. We prove that __h(n__) = [__n__^2^/4]+1 (__n__ β§ 4) and discuss some related problems.
On graphs with hamiltonian squares
β Scribed by P. Underground
- Publisher
- Elsevier Science
- Year
- 1978
- Tongue
- English
- Weight
- 111 KB
- Volume
- 21
- Category
- Article
- ISSN
- 0012-365X
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β¦ Synopsis
The problem of recognizing hamiltonian graphs is not Jriously difficult; in fack, Karp, Lawler and Tarjan [3] proved that it is NP-colnplete. Combined with Cook's theorem [l], this result suggests that the existence'= of a good characterization of nonhamiltcnian graphs is extremely unlikely. On the other hand, the problem of recognizing graphs with hamiltonian squares may seem easier, in view of Fleischner's [Z] proof of the conjecture due to Nash-iViPlia:ns and Plummer: every 'R-connected graph has a hamiltonian square. We shall point out that the two problems are, in fact, equivalent: given a graph G, we shall construct a graph H such that G is hamiltonian if ;and only if H2 is hamiltonian.
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π SIMILAR VOLUMES
## Abstract One of the most fundamental results concerning paths in graphs is due to Ore: In a graph __G__, if deg __x__ + deg __y__ β§ |__V__(__G__)| + 1 for all pairs of nonadjacent vertices __x, y__ β __V__(__G__), then __G__ is hamiltonianβconnected. We generalize this result using set degrees.
In this paper it is shown that any rn-regular graph of order 2rn (rn 3 3), not isomorphic to K, , , , or of order 2rn + 1 (rn even, rn 3 4), is Hamiltonian connected, which extends a previous result of Nash-Williams. As a corollary, it is derived that any such graph contains at least rn Hamiltonian
We show that every 3-connected claw-free graphs having at most 5S-10 vertices is hamiltonian, where 6 is the minimum degree. For regular 3-connected claw-free graphs, a related result was obtained by Li and Liu (preprint), but for nonregular claw-free graphs the best-known result comes from the work
## Abstract In this paper, __k__ + 1 real numbers __c__~1~, __c__~2~, β, __c__~__k__+1~ are found such that the following condition is sufficient for a __k__βconnected graph of order __n__ to be hamiltonian: for each independent vertex set of __k__ + 1 vertices in __G__. magnified image where S~i~