Intermediate subgroups of braid groups are not bi-orderable

Abstract

Let $M$ be the disk or a compact, connected surface without boundary different from the sphere $S^2$ and the real projective plane $\mathbb{R}{P}^2$, and let $N$ be a compact, connected surface (possibly with boundary). It is known that the pure braid groups $P_n(M)$ of $M$ are bi-orderable, and, for $n\ge 3$, that the full braid groups $B_n(M)$ of $M$ are not bi-orderable. The main purpose of this article is to show that for all $n\ge 3$, any subgroup $H$ of $B_n(N)$ that satisfies $P_n(N)⊊H\subset B_n(N)$ is not bi-orderable.

14 pages, 1 figure