 Braid group

The group of braids on $n$ strands, composed by stacking, with adjacent-crossing generators ${\sigma }_i$ and the braid group relations. It retains over/under crossings and is not a permutation group.

The braid group is a mathematical structure that arises in the study of braids, which can be visualized as strands intertwined in a particular way. It is a fundamental concept in the fields of topology, algebra, and mathematical physics.