... Math.109(1993), 557–561.[7] R.FoxandL.Neuwirth,The braid groups, Math. Scand.10(1962), 119–126.[8] G.I. Lehrer and L. Solomon, On the action of the symmetric group on the coho-mology of ... combinatorics 4 (1997), #R4 12[5] P. Edelman and V. Reiner, Free hyperplane arrangements between An and Bn,Math. Z.215(1994), 347–365.[6] H Esnault, E. Viehweg, and V. Schechtmann, Cohomology of ... topology,Addison-Wesley,MenloPark,CA,1984.[10] P. Orlik and L. Solomon, Combinatorics and topology of complements of hyper-planes, Invent. Math.56(1980), 167–189.[11] P. Orlik and H. Terao, Arrangements of hyperplanes,...