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Topological Criteria for $k-$Formal Arrangements

Stefan Ovidiu Tohaneanu
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Abstract

We prove a criterion for $k-$formality of arrangements, using a complex constructed from vector spaces introduced in \cite{bt}. As an application, we give a simple description of $k-$formality of graphic arrangements: Let $G$ be a connected graph with no loops or multiple edges. Let $Δ$ be the flag (clique) complex of $G$ and let $H_{\bullet}(Δ)$ be the homology of the chain complex of $Δ$. If $\mathcal A_G$ is the graphic arrangement associated to $G$, we will show that $\mathcal A_G$ is $k-$formal if and only if $H_i(Δ)=0$ for every $i=1,...,k-1$.

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Stefan Ovidiu Tohaneanu. 2006-08-17. Topological Criteria for $k-$Formal Arrangements. https://arxiv.org/abs/math/0608448

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