... formula, which expresses the ranks of the quotients of the lower central series of π1 of certain arrangements, incombinatorial terms. The LCS formula for pure braid groups was discoveredby Kohno, ... the discussion after the proof of Theorem 3.2. Polar curves, affine Lefschetz theoryand degree of gradient mapsThe use of the local polar varieties in the study of singular spaces isalready ... there.Proof of Theorem 1. In view of Hamm’s affine Lefschetz theory, see[H, Th. 5], the only thing to prove is the equality between the number kn of n-cells attached and the degree of the gradient.Assume...