中文

关于复反射构形限制的 $K(\pi, 1)$ 问题

代数拓扑 2020-02-19 v4 代数几何 群论

摘要

WGL(V)W\subset GL(V) 为一复反射群,A(W){\mathscr A}(W)WW 中复反射的镜面之集。已知反射构形 A(W){\mathscr A}(W) 的补集 X(A(W))X({\mathscr A}(W)) 是一个 K(π,1)K(\pi,1) 空间。对于 A(W)\mathscr A(W) 中超平面的一个交 YY,令 X(A(W)Y)X(\mathscr A(W)^Y)YY 中那些不包含 YYA(W)\mathscr A(W) 中超平面的补集。我们希望 X(A(W)Y)X(\mathscr A(W)^Y) 总是一个 K(π,1)K(\pi,1)。我们在单项群 W=G(r,p,)W = G(r,p,\ell) 的情形证明了这一点。利用已知结果,我们进而表明仅剩下三个不可约复反射群,导致仅有八种此类诱导构形的 K(π,1)K(\pi,1) 性质尚待证明。

关键词

引用

@article{arxiv.1708.05452,
  title  = {On the $K(\pi, 1)$-problem for restrictions of complex reflection arrangements},
  author = {Nils Amend and Pierre Deligne and Gerhard Roehrle},
  journal= {arXiv preprint arXiv:1708.05452},
  year   = {2020}
}

备注

20 pages; v2: small changes and further references added, in particular [AMR18], where examples of K(pi,1) arrangements are exhibited which admit restrictions that are not K(pi,1); v3 author added, completely revised, alternate geometric proof of main theorem, 11 pages; v4 minor changes, final version to appear in Compositio Math