Braided monoidal 2-categories and Manin-Schechtman higher braid groups

AbstractWe study a certain coherence problem for braided monoidal 2-categories. For ordinary braided monoidal categories such a problem is well known to lead to braid groups: If we denote by T(n) the pure braid group on n strands then this group acts naturally on each product A1 ⊗ · ⊗ An. It turns out that in the 2-categorical case we have to consider the so-called higher braid group T(2,n) introduced by Manin and Schechtman. The main result is that T(2,n) naturally acts by 2-automorphisms on the canonical 1-morphism A1 ⊗ · ⊗ An → An⊗ · ⊗ A1 for any objects A1,…, An