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A limit theorem for the $1$st Betti number of layer-$1$ subgraphs in random graphs

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 نشر من قبل Minghao Tian
 تاريخ النشر 2019
  مجال البحث الهندسة المعلوماتية
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We initiate the study of local topology of random graphs. The high level goal is to characterize local motifs in graphs. In this paper, we consider what we call the layer-$r$ subgraphs for an input graph $G = (V,E)$: Specifically, the layer-$r$ subgraph at vertex $u in V$, denoted by $G_{u; r}$, is the induced subgraph of $G$ over vertex set $Delta_{u}^{r}:= left{v in V: d_G(u,v) = r right}$, where $d_G$ is shortest-path distance in $G$. Viewing a graph as a 1-dimensional simplicial complex, we then aim to study the $1$st Betti number of such subgraphs. Our main result is that the $1$st Betti number of layer-$1$ subgraphs in ErdH{o}s--Renyi random graphs $G(n,p)$ satisfies a central limit theorem.



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