×

Vector braids. (English) Zbl 0999.20027

Summary: We define a new family of groups which generalize the classical braid groups on \(\mathbb{C}\). We denote this family by \(\{B^m_n\}_{n\geq m+1}\) where \(n,m\in\mathbb{N}\). The family \(\{B^1_n\}_{n\in\mathbb{N}}\) is the set of classical braid groups on \(n\) strings. The group \(B^m_n\) is related to the set of motions of \(n\) unordered points in \(\mathbb{C}^m\), so that at any time during the motion, each \(m+1\) of the points span the whole of \(\mathbb{C}^m\) in the sense of affine geometry. There is a map from \(B^m_n\) to the symmetric group on \(n\) letters. We let \(P^m_n\) denote the kernel of this map. In this paper we are mainly interested in finding a presentation of and understanding the group \(P^2_n\). We give a presentation of a group \(PL_n\) which maps surjectively onto \(P^2_n\). We also show the surjection \(PL_n\to P^2_n\) induces an isomorphism on first and second integral homology and conjecture that it is an isomorphism. We then find an infinitesimal presentation of the group \(P^2_n\). Finally, we also consider the analagous groups where points lie in \(\mathbb{P}^m\) instead of \(\mathbb{C}^m\). These groups generalize the classical braid groups on the sphere.

MSC:

20F36 Braid groups; Artin groups
20F05 Generators, relations, and presentations of groups
57M05 Fundamental group, presentations, free differential calculus
57M07 Topological methods in group theory

References:

[1] Birman, J., Braids, Links and Mapping Class Groups, (Annals of Mathematics Studies, vol. 82 (1974), Princeton Univ. Press: Princeton Univ. Press Princeton, NJ)
[2] Björner, A.; Ziegler, G., Combinatorial stratification of complex arrangements, J. Amer. Math. Soc., 5, 96-126 (1991)
[3] Breiskorn, E., (Sur les groups des tresses, Seminaire Bourbaki. Sur les groups des tresses, Seminaire Bourbaki, 1971/72. Sur les groups des tresses, Seminaire Bourbaki. Sur les groups des tresses, Seminaire Bourbaki, 1971/72, Lecture Notes in Mathematics, vol. 317 (1973), Springer: Springer Berlin), 21-44 · Zbl 0277.55003
[4] Chen, K.-T., Extension of \(C^∞\) function algebra and Malcev completion of \(π_1\), Adv. Math., 23, 181-210 (1977) · Zbl 0345.58003
[5] Chen, K.-T., Iterated integrals, Bull. Amer. Math. Soc. (N.S.), 83, 831-879 (1977) · Zbl 0389.58001
[6] Fadell, E.; Van Buskirk, J., The braid groups of \(E^2\) and \(S^2\), Duke Math. J., 29, 243-258 (1962) · Zbl 0122.17804
[7] Fadell, E.; Neuwirth, L., Configuration spaces, Math. Scand., 10, 111-118 (1962) · Zbl 0136.44104
[8] Goresky, M.; MacPherson, R., Stratified Morse Theory (1980), Springer: Springer Berlin
[9] Hain, R., Classical polylogarithms, (Proc. Symp. Pure Math., 55 (1994)), Part 2 · Zbl 0807.19003
[10] R. Hain, Topological arrangements, preprint.; R. Hain, Topological arrangements, preprint.
[11] Hain, R.; MacPherson, R., Higher logarithms, Ill. J. Math., 34, 392-475 (1990) · Zbl 0737.14014
[12] Jiang, T.; Yau, S., Topological and differentiable structures of the complement of an arrangement of hyperplanes, (Proc. Symp. Pure Math., 54 (1993)), Part 2 · Zbl 0795.57012
[13] Kohno, T., Linear representations of braid groups and classical Yang-Baxter equations, Contemp. Math., 78, 339-363 (1988) · Zbl 0661.20026
[14] Leibman, A., Fiber bundles with degenerations and their applications to computing fundamental groups, Geometriae Dedicata, 48, 93-126 (1993) · Zbl 0812.57004
[15] Orlik, P., Introduction to arrangements, (CBMS, Regional Conference Series in Mathematics, vol. 72 (1988)) · Zbl 0722.51003
[16] Randell, R., The fundamental group of the complement of a union of complex hyperplanes, Invent. Math., 69, 103-108 (1982) · Zbl 0505.14017
[17] Randell, R., The fundamental group of the complement of a union of complex hyperplanes: correction, Invent. Math., 80, 467-468 (1985) · Zbl 0596.14014
[18] R. Randell, The fundamental group of the complement of a union of complex hyperplanes: correction, unpublished manuscript.; R. Randell, The fundamental group of the complement of a union of complex hyperplanes: correction, unpublished manuscript. · Zbl 0596.14014
[19] Serre, J.-P., Lie Algebras and Lie Groups, (Lecture Notes in Mathematics (1992), Springer: Springer Berlin) · Zbl 0742.17008
[20] Sullivan, D., On the intersection ring of compact 3-manifolds, Topology, 14, 275-277 (1975) · Zbl 0312.57003
[21] Sullivan, D., Infinitesimal computations in topology, Publ. IHES, 47, 269-331 (1977) · Zbl 0374.57002
[22] T. Terasoma, Fundamental groups of moduli spaces of hyperplane configurations, preprint.; T. Terasoma, Fundamental groups of moduli spaces of hyperplane configurations, preprint. · Zbl 0884.14002
[23] Whitehead, G., Elements of Homotopy Theory (1978), Springer: Springer Berlin · Zbl 0406.55001
This reference list is based on information provided by the publisher or from digital mathematics libraries. Its items are heuristically matched to zbMATH identifiers and may contain data conversion errors. In some cases that data have been complemented/enhanced by data from zbMATH Open. This attempts to reflect the references listed in the original paper as accurately as possible without claiming completeness or a perfect matching.