We study the cycle structure of I-tough, triangle-free graphs. In particular, w e prove that every such graph on n 2 3 vertices with minimum degree 6 2 i ( n + 2) has a 2-factor. W e also show this is best possible by exhibiting an infinite class of I-tough, triangle-free graphs having 6 = $ ( n + 1
On triangle-free random graphs
✍ Scribed by Tomasz Łuczak
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 167 KB
- Volume
- 16
- Category
- Article
- ISSN
- 1042-9832
No coin nor oath required. For personal study only.
✦ Synopsis
We show that for every k ≥ 1 and δ > 0 there exists a constant c > 0 such that, with probability tending to 1 as n → ∞, a graph chosen uniformly at random among all triangle-free graphs with n vertices and M ≥ cn 3/2 edges can be made bipartite by deleting δM edges. As an immediate consequence of this fact we infer that if M/n 3/2 → ∞ but M/n 2 → 0, then the probability that a random graph G n M contains no triangles decreases as 2 -1+o 1 M . We also discuss possible generalizations of the above results.
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