{ "id": "2309.02993", "version": "v1", "published": "2023-09-06T13:36:39.000Z", "updated": "2023-09-06T13:36:39.000Z", "title": "Counting triangles in regular graphs", "authors": [ "Jialin He", "Xinmin Hou", "Jie Ma", "Tianying Xie" ], "categories": [ "math.CO" ], "abstract": "In this paper, we investigate the minimum number of triangles, denoted by $t(n,k)$, in $n$-vertex $k$-regular graphs, where $n$ is an odd integer and $k$ is an even integer. The well-known Andr\\'asfai-Erd\\H{o}s-S\\'os Theorem has established that $t(n,k)>0$ if $k>\\frac{2n}{5}$. In a striking work, Lo has provided the exact value of $t(n,k)$ for sufficiently large $n$, given that $\\frac{2n}{5}+\\frac{12\\sqrt{n}}{5}