We give a formula for factorizing the full twist in the braid group Br2m in terms of four factorizations of the full twist in Brm. This formula is used to construct a symplectic 4-manifold X and two regularly homotopic generic coverings f_i: X →CP~2 branched along cuspidal Hurwitz curves H-bar_i is contained in CP~2 (without negative nodes) having different braid monodromy factorization types. The class of fundamental groups of complements of affine plane Hurwitz curves is described in terms of generators and defining relations.
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