Homomorphisms between braid groups

Lei Chen, Kevin Kordek, Dan Margalit

Published 2019-10-01Version 1

We give a complete classification of homomorphisms from the braid group on $n$ strands to the braid group on $2n$ strands when $n$ is at least 5. We also classify endomorphisms of the braid group on 4 stands. Our classifications suggest a recursive classification of homomorphisms between any braid groups. We also give a simple, geometric proof of a theorem of Lin that highly constrains the holomorphic maps that may exist between spaces of monic, square-free polynomials of a given degree.