Lei Chen

activity

20172022

most citedThe universal surface bundle over the Torelli space has no sections

1 citations · 2 across the 7 of their papers we have counts for

collaborators

Showing 2018Show all

4 papers · 1 filter

math.GT2018

Adding a point to configurations in closed balls

Lei Chen, Nir Gadish, Justin Lanier

We answer the question of when a new point can be added in a continuous way to configurations of $n$ distinct points in a closed ball of arbitrary dimension. We show that this is p…

math.GT2018

On the non-realizability of braid groups by homeomorphisms

Lei Chen

In this paper, we will show that the projection $Homeo^{+} (D_{n}^{2}) \to B_{n}$ does not have a section; i.e. the braid group $B_{n}$ cannot be geometrically realized as a group of ho…

math.GT2018

Section problems for configurations of points on the Riemann sphere

Lei Chen, Nick Salter

This paper contains a suite of results concerning the problem of adding $m$ distinct new points to a configuration of $n$ distinct points on the Riemann sphere, such that the new p…

math.GT2018

The Birman exact sequence does not virtually split

Lei Chen, Nick Salter

This paper answers a basic question about the Birman exact sequence in the theory of mapping class groups. We prove that the Birman exact sequence does not admit a section over any…