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arXiv · math/9501229

Not all free arrangements are $K(π,1)$

Paul H. Edelman·Victor Reiner
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Abstract

We produce a one-parameter family of hyperplane arrangements that are counterexamples to the conjecture of Saito that the complexified complement of a free arrangement is $K(π,1)$. These arrangements are the restriction of a one-parameter family of arrangements that arose in the study of tilings of certain centrally symmetric octagons. This other family is discussed as well.

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Paul H. Edelman, Victor Reiner. 1995-01-01. Not all free arrangements are $K(π,1)$. https://arxiv.org/abs/math/9501229

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