Times: 2025 Aug 11 from 11:00AM to 11:25AM (Central Time (US & Canada))
Webinar link: Webinar
Abstract:
For any d > 0, define $G(\mathbb{Q}^n, d)$ to be the graph whose vertices are points of the rational space $\mathbb{Q}^n$ with any two vertices being adjacent if and only if they are a Euclidean distance $d$ apart. Such a graph is only of interest if $d$ is a distance actually realized between points of $\mathbb{Q}^n$, so we might as well assume that is the case. In this talk, we will ask for which $n$ and distances $d_1, d_2$ the graphs $G(\mathbb{Q}^n, d_1)$ and $G(\mathbb{Q}^n, d_2)$ are isomorphic. A resolution will be given for $n \leq 4$, and we will then present, by way of drawing a bunch of pictures, a method that, perhaps with some ingenuity, could be extended to answer this question for general $n$.
Notes:
Keywords: Euclidean distance graph, rational points, isometry, graph isomorphism